The Mollusca of the Genus Charonia (Family Cymatiidae)

Transactions of the Royal Society of New Zealand : Biological Sciences, Volume 11, Issue 16, 11 March 1970, Page 205

The Mollusca of the Genus Charonia (Family Cymatiidae)

A. G. Beu

By

New Zealand Geological Survey, Lower Hutt.

[Received by the Editor 17 February 1969 .]

Abstract

The forms of Charonia are placed in two species, C. tritonis (Linnaeus, 1758) and C. lampas (Linnaeus, 1758). C. tritonis has two geographic subspecies: C. tritonis tritonis in the Indo-Pacific; and C. tritonis variegata (Lamarck, 1816) in the Atlantic and in the Mediterranean. C. lampas has five geographic subspecies: the nominate one in the Mediterranean and in the eastern Atlantic; C. lampas pustulata (Euthyme, 1889) in South Africa; C. lampas sauliae (Reeve, 1844) in Japan; C. lampas rubicunda (Perry, 1811) in Australia; and C. lampas capax Finlay, 1927, in New Zealand and in the Kermadec Islands. C. lampas rubicunda occasionally occurs in New Zealand, apparently a result of transport of larvae across the Tasman Sea. Names based on deep water ecophenotypes in Australia and in Japan are synonymised with the earliest available names.

The genus first appears in the Oligocene of Europe, apparently evolving through genera resembling Vernotriton and Negyrina.

Introduction

The cymatiid gastropod Charonia tritonis is one of the largest and most spectacular of Indo-West Pacific shells. Members of the genus Charonia have been used as utensils and musical instruments by coastal and island peoples wherever the genus occurs, and are among the most familiar of molluscs. The many names for forms in the genus are here reduced to a total of seven geographic subspecies falling into two species.

In Australia, and lately in Japan, deep water forms of Charonia lampas have been considered as distinct species or subspecies. They are taller, more lightly built, paler than and often slightly differently sculptured from shallow water forms. A tall, thin-shelled deep water form has also been recorded in C. tritonis variegata by Clench and Turner (1957: 196). Tall deep water forms have been recorded in Mayena, Austrosassia, Negyrina and Cabestana, and may well occur in most or all Cymatiidae with large depth ranges. In the genera mentioned above (except Negyrina) , similar deep water forms have been collected in New Zealand, where they are found to intergrade with shells from intermediate and shallow depths. It is considered that the distinctive characters of the deep water forms of Cymatiidae must be largely or entirely ecophenotypic. The many names erected for such forms in the genus Charonia in Australia are here synonymised with the earliest one. In Australia and New Zealand there is a further complication in the roughly clinal variation of Charonia lampas subspecies, which is discussed under the individual taxa.

Taxonomy

Family CYMATIIDAE Iredale, 1913 Subfamily CHARONIINAE Powell, 1933

Genus Charonia Gistel [1847]

1798. Tritonium “Cuvier” Roeding, Museum Boltenianum: 125 (not Mueller, 1776). Type species (by tautonymy) :T. tritonis Linnaeus ( = Murex tritonis Linnaeus, 1758).

1810. Triton Montfort, Conchyliologie Systematique 2: 587 (not Linnaeus, 1758; not Laurenti, 1768). Type species (by monotypy) : Triton tritonis Montfort, 1810 (in part Murex tritonis Linnaeus, 1758; in part Charonia capax Finlay, 1927). Not Triton Fleming, 1828 (= Tritonalia Fleming, 1828), Muricidae; I.C.Z.N. pending.

1822. Tritonium “Montfort” Bowditch, Elements of Conchology (1): 36 (not Mueller, 1776; not Roeding, 1798); emend, of Triton Montfort, 1810.

[1847]. Charonia Gistel, Handbuch der Naturgesellschaft: 559; 1848, Naturgeschichte das Thierreich fur hohere Schulen: 170.

1877. Buccinatorium Moerch, Malakozoologische Blatter 24: 26. Type species (by subsequent designation. Clench and Turner, 1957): Triton nohile Conrad, 1848 ( = T. variegatum Lamarck, 1816).

1877. Tritonellium “Valenciennes” Moerch, Malakozoologische Blatter 24: 25 (not Tritonellium Valenciennes, 1858).

1901, Septa “Perry” Dali and Simpson, U.S. Fisheries Comm. Bull. 1900(1): 416 (not Septa Perry, 1810); 1904, Dali, Smithson, misc. Colins 47: 134.

1904. Eutritonium Gossman, Essais de Paleoconchologie Gomparee 6: 123. Type species (by original designation) : Murex tritonis Linnaeus, 1758.

1912. Nyctilochus “Gistel” Dali, The Nautilus 26: 58 (not Nyctilochus Gistel, 1848).

Type species (by monotypy): Murex tritonis Linnaeus, 1758, Recent, Indo-Pacific.

The genus name has more synonyms than almost any other molluscan genus. After Montfort, most workers for almost a century used Triton for all Cymatiidae, although they knew it to be preoccupied by a name erected by Linnaeus. Dali and Simpson (1901: 416) instituted the use of Septa Perry, “ 1811 ” for Murex tritonis, but Mathews and Iredale (1912 )showed that Septa dated from Perry’s “ Arcana”, 1810, where it was monotypic, and that it should be used in place of Lampusia Schumacher, 1817. Dali (1912: 58) then suggested the use of Nyctilochus Gistel, 1848, for Murex tritonis, but Iredale (1913: 55) showed that Nyctilochus was proposed for Triton “ Montfort” Broderip, as used in Isis van Oken for 1835, column 453 (error for 452), where the only Cymatiidae listed are species now placed in Distorsio [Rhysema), Cymatium s.str., Priene, Turritriton and Reticutriton. Triton tigrinus Broderip, 1833, is here designated the type species of Nyctilochus Gistel, 1848, so that the name is a junior subjective synonym of Cymatium Roeding, 1798. In the same work Gistel (1848) used the name Charonia for Murex tritonis Linnaeus, and this was considered by Iredale (1913) to be the earliest available name for the genus. This has been quoted as the earliest reference to Charonia by most recent workers, but Iredale and McMichael (1962: 54) quoted the name as of Gistel and Bromme, 1847, and this was followed by Powell (1964: 14). Neave (1939: 674) gave Charonia as dating from Gistel “ [1847], Handh. Naturges., 1850, 559, 586”, and also gave the 1848 reference. The earlier work is apparently dated 1850, but appeared in 1847. It is not available in New Zealand, so I have accepted Neave’s reference to its authorship, and quote Charonia as of Gistel [1847]. Charonia is thus earlier than Nyctilochus.

Winckworth (1934: 14) and Dodge (1957: footnote to p. 97) considered that Tritonalia Fleming, 1828, should be interpreted as a substitute name for Triton Montfort, 1810, and was therefore an earlier name for Charonia. However, Yokes (1964: footnote to pp. 19, 20) and most other authors have interpreted Tritonalia Fleming as a new name for the muricid genus Fleming had called Triton in the

same work, and Yokes used the name as a valid senior synonym of Ocenebra Gray, 1847, using the family-group name Tritonaliinae based upon it. Keen (1964: 237) discussed the case further, and (p. 239) requested the International Commission on Zoological Nomenclature to place Gharonia on the Official List of Generic Names in Zoology, and to place Tritonalia on the Official Index of Rejected and Invalid Generic Names in Zoology. In view of the long-standing confusion over the use of Tritonalia this solution seems eminently sensible. The only usages of Tritonalia in the sense of Gharonia I have seen are by Kuroda and Habe (1952: 92), Tinker (1952), and Kira (1955: 43).

Diagnosis : Shell large to very large, elongate, with a tall spire and short anterior canal and base. Sculpture dominantly spiral, of low cords with one or several interstitial threads, or of threads only; axial sculpture consisting of low, weak folds in a narrow band below the suture and of several peripheral and lower rows of knobs. Varices well developed, spaced about every 270° around the shell, merging into the shell abaperturally but prominent adaperturally, and bearing the remains of the flaring outer lip in front. Inner lip rather broad, bearing one or two callus ridges near the posterior canal, and sculptured below with irregular plicae that are often developed on the top of the anterior canal only. Colour cream, pink or fawn marbled with darker reddish brown splashes. Protoconch of five smooth, rounded whorls, rather short and turbinate, with a brown, horny outer layer and a thin, pink, shelly inner layer; usually missing in adults. Periostracum of teleoconch very thin, pale straw coloured, smooth or lightly wrinkled, readily deciduous, perhaps even totally absent in C. tritonis. Operculum thick, dark brown, oval with a central nucleus and complete concentric growth lines in C. tritonis, oval with a slight anterior hook to the left, an anterior sub terminal nucleus and incomplete concentric growth lines in C. lampas. Radula highly distinctive; of typical taenioglossan type, but with the central tooth broad and low, with a very narrow basal plate that is curved down at the extremities; all other teeth narrow and elongate.

The most distinctive feature of the genus is its radula, but it can also be readily separated from other Cymatiidae by its very large size, tall conoidal spire and short base and anterior canal, the form of the varices and the reduced periostracum.

Gharonia tritonis (Linnaeus, 1758) This species reaches a very large size, being probably the third largest of all gastropods. The spire and general shell shape are tall and narrow. The outer lip flares markedly. The inner lip bears prominent white plicae on a dark brown background over its whole length, and the interior of the outer lip bears paired dark brown teeth on a pale background. The spiral sculpture consists of broad cords with a single narrow thread filling each interspace, and nodules are low or absent. The shell surface is extremely glossy, and there appears to be almost no periostracum. The colour pattern is very bright, with a marked contrast between the red-brown crescentic axial splashes and the pink or cream background.

Clench and Turner (1957: pi. 111, figs. 1,2) figured the operculum of a specimen of C. tritonis variegata, and also figured the radula (pi. 113, fig. 1) and an embryonic shell with well-preserved protoconch (pi. 114, fig. 2) of the same form. The radula shows important differences from that of C. lampas; the extremities of the basal plate of the central tooth are bent downwards much further, and the inner lateral tooth is broader.

Two very similar forms of C. tritonis occur in the Indo-Pacific and Atlantic oceans respectively, and, in a modern polytypic species concept, these can be considered only as geographic subspecies worthy of trinomial nomenclature. The two forms are figured excellently and their distinguishing characters discussed by Clench and Turner (1957: 193 et seq.) . Such subspecies pairs are frequent in the Pacific and the western Atlantic because of the former connection of the two oceans through the site of the present Isthmus of Panama.

Charonia tritonis tritonis (Linnaeus, 1758). PI. 1, Figs. 1-4.

1758. Murex tritonis Linnaeus, Systema Naturae, ed. 10: 754 (in part, references to Bonanni and Rumpf only; Bonanni, “ Recreatio Mentis Oculi ”, etc., fig. 188 was selected as type figure by Clench and Turner, 1957: 196).

1767. Murex tritonis : Linnaeus, Systema Naturae, ed. 12: 1222.

1807. Triton marmoratum Link, Beschr. Nat.-Samm. Univ. Rostock: 122 (in part, reference to Gmelin only; this refers to Bonanni, “Recreatio”, etc., fig. 188, and was selected as type figure of marmoratum by Clench and Turner, 1957: 196).

1810. Triton tritonis Montfort, Conchyliologie Systematique 2: 587 (in part; Montfort’s figured specimen is C. lampas capax from New Zealand).

1822. Triton variegatum Lamarck, Animaux sans Vertebres 7: 178 (in part).

1844. Triton variegatus ; Reeve, Conch. Icon. 2, Triton : pi. 2, fig. 3b (typical variety only).

1852. Tritonium tritonis : H. and A. Adams, Genera of Recent Mollusca 1: 102; 1858, Vol. 3: pi. 11, fig. Ic.

1873. Triton variegatum : Hutton, Cat. Mar. Moll. New Zealand: 12.

1881. Triton tritonis: Tryon, Man. Conch. 3: 9, pi. 1, fig. 1; pi. 3, fig. 16; pi. 5, fig. 25 (not pi. 4, as given in text).

1913. Septa tritonis: Suter, Man. N.Z. Moll.: 304, pi. 42, fig. 1. 1933. Charonia tritonis: Bayer, Zool. Meded. Leiden 16: 56.

1936. Charonia tritonis: Hirase, A Collection of Japanese Shells in Nat. Colours, etc.: 66, pi. 95, fig. 9.

1941. Charonia tritonis: Hatai, Bull. Imp. Trop. Industr. Res. Inst. Palau 7: 122, pi. 3, figs. 1,2.

1951. Charonia tritonis: Taki, An 111. Handbook of Shells in Nat. Colours from the Japan. Is., etc.: pi. 95, fig. 9.

1952. Tritonalia tritonis: Kuroda and Habe, Checklist Bibliogr. Mar. Moll. Japan: 92.

1952. Tritonalia tritonis: Tinker, Pacific Sea Shells: 88, unnumbered fig.

1954. Charonia tritonis: Bellatante, J. Conch. Paris 94: 70.

1955. Tritonalia tritonis: Kira, Coloured 111. Shells of Japan, ed. 1: 43, pi. 21, fig. 15.

1956. Charonia tritonis: Kaicher, Indo-Pacific Sea Shells, Tonnacea: pi. 4, fig. 1.

1959. Charonia tritonis: Allan, Australian Shells, ed. 2: 111, pi. 1, fig. 3.

1961. Charonia tritonis: Kira, Coloured 111. Shells of Japan, ed. 2: 53, pi. 21, fig. 12.

1961. Charonia tritonis: Rippingale and McMichael, Queensland and Great Barrier Reef Shells: 67, pi. 7, fig. 8.

1962. Charonia tritonis : Kira, Shells of the Western Pacific in Colour: 56, pi. 22, fig. 12.

1963. Charonia tritonis: Barnard, Ann. Sth. Afr. Mus. 47: 26 (with further synonymy).

1964. Charonia tritonis: Powell, Rec. Auckland Inst. Mus. 6(1); 14.

1967. Charonia tritonis: Cemohorsky, the Veliger 9(3); 326, pi. 46, fig. 27.

Grows considerably larger than Atlantic form, and is considerably narrower in shape at same size. Periphery regularly rounded, bearing no knobs, or only weak ones. Outer lip flaring markedly, teeth on its inner surface weak or absent over central portion. Plicae on inner lip low and broad, and separated by dark brown interstices narrower than width of plicae.

C. tritonis tritonis is distributed throughout the Indo-West Pacific faunal province. Specimens are recorded from Kyushu, the southern island of Japan, and farther south (Kira, 1962: 56) and from Durban, South Africa (Barnard, 1963: 26) and presumably occur along the coasts of Africa and Asia between these extremes; in the east the subspecies extends to Hawaii, and probably as far southeast as the Tuamotu Archipelago and Pitcairn Island. It is also recorded from most islands within the area outlined by the few records mentioned. In Australasia it occurs throughout northern Western Australia, the Northern Territory and Queensland, and has been recorded from Lord Howe Island; two undoubted specimens have been collected in northern New Zealand.

New Zealand specimens have been reported from Wainui Bay, Whangaroa, Northland (Powell, 1964; 14), and from Cape Maria van Diemen and Reef Point,

Ahipara (Suter, 1913: 304), but the latter two records are considered doubtful. Hutton (1873: 12) noted: “Dr Dieffenbach brought this species to England from Cape Maria van Diemen,” and this is probably the source of Suter’s record from the locality. Through the courtesy of Dr A. W. B. Powell, the writer has recently examined a second undoubted specimen in good condition, collected at Rosalie Bay, an isolated locality on Great Barrier Island (recorded by Powell, 1967: 187). There are also recent unconfirmed reports of living specimens having been taken frequently in crayfish pots and on anchor lines near the entrance to Houhora Harbour, Northland. Thus the species seems definitely to occur in New Zealand, and its larvae are apparently able to survive and metamorphose in relatively cool waters. It seems unlikely that C. tritonis tritonis is able to reproduce in New Zealand.

Dimensions: C. tritonis tritonis reaches about 18 inches in length. The largest specimen I have examined, in the Dominion Museum, Wellington, from Fiji, is 395 mm high and 215 mm broad, and the figured specimen, from Rosalie Bay, Great Barrier Island, New Zealand, is 340 mm high and 180 mm broad. Juvenile specimens are considerably narrower than adults; the figured juvenile, in the Dominion Museum, is 116.4 mm high and 37.5 mm broad.

Charonia tritonis variegata (Lamarck, 1816). PI. 2, Figs 5, 7.

1758. Murex tritonis Linnaeus, Systema Naturae, ed. 10: 754 (in part, reference to Gaultieri only).

1807. Triton marmoratum Link, Beschr. Nat.-Samm. Univ. Rostock; 122 (in part, reference to Chemnitz only).

1816. Triton variegatum Lamarck, Tableau Encyclopedique et Methodique: Liste, p. 5; Atlas 3, pi. 421, figs. 2a, 2b.

1822. Triton variegatum : Lamarck, Animaux sans Vertebres 7: 178 (in part)

1822. Tritonia atlantica “ Montfort ” Bowditch, Elements of Conchology (1); pi. 10, fig. 4.

1844. Triton variegatus var. /3 Reeve, Conch. Icon. 2, Triton: pi. 1, fig. 3a.

1848. Triton nobilis Conrad, Proc. Acad. Nat. Sci. Phila. 4: 121.

1870. Tritonium seguenzae Aradas and Benoit, Conch, viv. marina della Sicilia: pi. 4, fig. 1 (fide Pallary, 1938).

1871. Tritonium seguenzae: Aradas and Benoit, Atti dell’Accad. Gioenia di Sci. Nat. di Catania 3(5); 90.

1876. Triton commutatus “ Dunker ” Kobelt, in Martini and Chemnitz, Systematisches Conchylien-Cabinet, ser. 2, 3(2); 224 ( nomen nudum).

1881. Triton tritonis var. nobilis: Tryon, Man. Conch. 3: 10, pi. 4, figs. 21, 26.

1889. Tritonium seguenzae: Kobelt, Inconogr. Europ. Meeresconchylien 2: 19, pi. 35, fig. 1; pi. 36, fig. 1; pi. 37, fig. 1.

1933. Charonia tritonis var. nobilis: Bayer, Zool. Meded. Leiden 16: 57.

1938. Tritonium seguenzae, with vars. minor and major Pallary, J. Conch. Paris 82: 29.

1954. Charonia tritonis var. nobilis : Bellatante, J. Conch. Paris 94: 70.

1954. Charonia tritonis nobilis: Abbott, American Seashells: 197, pi. 5, fig. f.

1957. Charonia variegata: Clench and Turner, Johnsonia 3(36) : 103, pi. 111, figs. 1, 2; pi. 113, fig. 1; pi. 114, figs. 1,2 (with further synonymy).

1961. Charonia variegata: Warmke and Abbott, Caribbean Seashells: 99, pi. 1, fig. A.

1962. Charonia species: Weisbord, Bull. Am. Paleont. 42(193): 266, pi. 25, figs. 9-11.

Very similar to Pacific subspecies, but does not reach the enormous size of that form and has a relatively shorter spire. Whorls are slightly shouldered and periphery bears low, rounded nodules. Outer-most portion of outer lip flares as in nominate subspecies, but portion inside thickest part of labial varix is considerably constricted, so that aperture more nearly resembles that of other Gymatiidae than does that of C. tritonis tritonis. Teeth on inner surface of outer lip always strongly developed. Plicae on inner lip higher and narrower than in C. tritonis tritonis, so that dark brown interstices are considerably wider than in that form. Colour pattern and sculpture of the two subspecies are identical.

C. tritonis variegata is widely distributed on both sides of the central Atlantic Ocean and in the Mediterranean Sea. In the western Atlantic it is recorded from Bermuda, the Bahama Islands, the lower Florida Keys, the West Indies and from central Mexico to Santos, Brazil (Clench and Turner, 1957: 197). In the eastern Atlantic it occurs in the Cape Verde Islands, the Canary Islands and St. Helena (Clench and Turner, 1957: 197), Portugal (Tryon, 1881: 10) and probably on the mainland coasts of Africa along this area. In the Mediterranean Sea it is known from Malta (Gatto and Despott, 1919), Sicily (Tryon, 1881: 10) and from Beirut and Cyprus (Clench and Turner, 1957: 197). Pallary (1938: 29) recorded the subspecies (as seguenzae) from Beirut, Tripoli and Batrun in the Lebanon and from three localities that I have been unable to trace, Jounieh, Fadaousse and Rouacl. Probably the species occurs rarely throughout the Mediterranean. I have seen no records from the Morocco-Tunisia coast, but it seems likely that it occurs there.

In the March, 1967, issue of Hawaiian Shell News (p. 8) a letter was published from a shell collector, Sr Estabon Calderon, of Rio Muni (Spanish Guinea). He reported the collecting of an eight-inch, badly worn, living specimen of Charonia related to tritonis and variegata, at Annobon Island in the Gulf of Guinea. The specimen is figured, and from its apertural features is clearly C. tritonis variegata (Lamarck). Sr Calderon stated: "It is the first specimen of Charonia found in West Africa distinct from Charonia nodiferum" [i.e., Charonia lampas lampas (Linnaeus)]. Thus the form seems to be very rare on the coast of Africa south of Cape Verde, and the extreme southern point reached is not yet clear.

The only fossil occurrence of a member of the C. tritonis group known to me is that recorded by Weisbord (1962: 266). He figured fragments of C. tritonis aff. variegata from Cabo Blanco, Venezuela (Pliocene?).

Dimensions: The largest specimen recorded by Clench and Turner (1957: 196) is the specimen they figure, from St. Thomas, Virgin Islands, 331 mm high and 168 mm broad. The specimen figured as PL 2, Figs. 5,7, from Lamentin, Martinique, in the New Zealand Geological Survey (WM9308), is 217 mm high and 106 mm broad.

Charonia lampas (Linnaeus, 1758)

A group of veiy similar, relatively small forms of Charonia is widely distributed over the world, each form occupying a restricted geographical area. The question of the oldest name for the earliest known member of the group, from the Mediterranean and the eastern Atlantic, has been a cause of much discussion and confusion over a great many years, due to the incorrect interpretation by most authors of Linnaeus' species Murex lampas. Smith (1914) and Dodge (1957) both concluded that Murex lampas was incontrovertibly the cymatiid known for many years as Charonia nodifera (Lamarck), rather than Bursa lampas of authors, and this usage is followed here.

The various forms around the world were often ranked as subspecies or varieties of nodifera or lampas during the early part of this century, but lately they have been treated as full species and in some regions have been subdivided into further species and subspecies. The opinion of Iredale (1915: 459) that all world forms belonged to one species seems much more like the modern concept of population taxonomy than the later subdivision of Australian forms would suggest. There are constant, but slight differences between the members of the group, and their relationships seem best expressed by ranking them as geographic subspecies of one species. Biological evidence that this is the relationship is available only in Australia and New Zealand, but the evidence provided there indicates that the forms are able to interbreed and that their larvae are transported over large areas of ocean. The five forms are thus ranked here as geographic subspecies of Charonia lampas (Linnaeus).

The species reaches a considerably smaller adult size than that of C. tritonis, and the spire is shorter. The whorls are always shouldered, and bear more prominent knobs than in either form of C. tritonis. The interstitial spiral threads are more numerous and more prominent in C. lampas than in C. tritonis, and the plicae and colouring of the inner lip of C. tritonis are much weaker or absent in C. lampas. The plicae of the outer lip are paired in C. tritonis but are single in C. lampas. The colour pattern of C. lampas is similar to that of C. tritonis but is much less brilliant, the contrast of the dark splashes and the pale background being much less marked, and the darker splashes are not regularly crescentic as in C. tritonis. The shell surface is dull or at most lightly polished in C. lampas, whereas it is extremely glossy in C. tritonis. The periostracum of C. tritonis seems to be very thin or perhaps totally absent, whereas that of C. lampas is quite thin, but is present as a deciduous brown coating on the lower whorls of all live-collected specimens. A major distinction is seen in the operculum, which has a central nucleus and complete concentric growth lines in C. tritonis but has a subterminal nucleus a little to the right of the lower margin and incomplete concentric growth lines in C. lampas. Radular differences were described under C. tritonis. In the radula of C. lampas capax Finlay the central tooth is markedly elongate, with a narrow basal plate having the extremities bent sharply down, and the other teeth are elongate, narrow and in most radulae lack accessory denticles.

The subspecies of C. lampas can be differentiated on the size of the nodules, the early sculpture of the spire, the strength of the plicae on the inner lip and, in particular, the strength and number of the interstitial spiral threads. Colour also is useful in some cases. Three of the subspecies, C. lampas lampas, lampas sauliae and lampas capax, are very similar in all features, and are difficult to separate if only a few specimens are examined; they differ mainly in the details of the interstitial and early spire sculpture. The other two, C. lampas ruhicunda and lampas pustulata, are more similar to each other than they are to the other three, but are readily differentiated on the strength of the secondary spiral sculpture (which is most prominent in C. lampas ruhicunda) , the size of the nodules (which are large in pustulata but almost absent in ruhicunda) and on the colour. C. lampas ruhicunda and C. lampas capax are found interbreeding in New Zealand, so that members of these two rather dissimilar subspecies groups are not considered to belong to different species.

Charonia lampas lampas (Linnaeus, 1758). PI. 2, Figs. 6, 9.

Not Bursa lampas of authors, = Tutufa rubeta (Linnaeus) and related forms.

1758. Murex lampas Linnaeus, Sytema Naturae, ed. 10: 748 (in part, reference to Rondelet only; Rondelet, 1555, “ Libri de Piscibus”, etc. (2): 81, is here designated the type figure of Murex lampas Linnaeus).

1767. Murex lampas : Linnaeus, Systema Naturae, ed. 12: 1216 (in part). 1798. Tritonium opis “ Bolten ” Roeding, Museum Boltenianum (2): 125.

1814. Murex gyrinoides Brocchi, Conch. Foss. Subappenina 2: 401, pi. 9, fig. 9.

1822. Triton nodiferum Lamarck, Animaux sans Vertebres 7: 179.

1826. Triton Mediterraneum Risso, Hist. Nat. de I’Europe Merid. etc. 4: 203.

1836. Tritonium variegatum “Lamarck”: Philippi, Enum. Moll. Siciliae 1: 212 (not Triton variegatum Lamarck, 1816).

1840. Triton ventricosum Grateloup, Conch. Foss, du Bassin de I’Adour, Atlas: pi. 29, fig. 17.

1840. Triton crassum Grateloup, Conch. Foss, du Bassin de PAdour, Atlas: pi. 29, fig. 20.

1844. Triton nodiferus: Reeve, Conch. Icon. 2, Triton : pi. 3, fig. 9.

1847. Triton ranellaeformae Sismonda in Michelotti, Foss. Mioc.: 252 (not seen; fide Bellardi, 1873).

1852. Triton erassum: d’Orbigny, Prodrome de Palaeontologie 3; 15.

1852. Tritonium opis: H. and A. Adams, Genera of Recent Mollusca 1: 102.

1856. Triton nodiferum: Hoernes, Die Fossilien Mollusken des Tertiaer-Beckens von Wien, 1: 201, pi. 19, figs. 1,2.

1869. Triton nodifer : Jeffreys, British Conchology 4: 301; 5: 218, pi. 83, fig. 3.

1873. Triton nodiferum: Bellardi, I Molluschi dei Terreni Terziari del Piemonte e della Liguria 1: 207 (with further synonymy).

1873. Triton ranellaeforme: Bellardi, Moll. Piemonte e Liguria 1: 208, pi. 14, fig. 1 (with further synonymy).

1873. Triton crassum : Bellardi, Moll. Piemonte e Liguria 1: 209, pi. 14, fig. 2.

1881. Triton nodiferus ; Tryon, Man. Conch. 3: 10 (in part; pi. 1, figs. 2, 3 only).

1882. Triton nodiferus : Bucquoy, Dautzenberg and Dollfus, Les Mollusques Marins du Rousillons 1(1): 29, pi. 4, fig. 1.

1886. Tritonium glabrum Locard, Cat, Gen. Moll. France: 154, 558 (not seen).

1886. Triton nodifer : Watson, “Challenger” Rep. Zool. 15: 389 (in part).

1900. Simpulum nodiferum, with vars. major and minima Pallary, J. Conch. Paris 48: 293.

1913. Tritonium nodiferum: Buchner, Schrifter des Deutschen Lehrer-Vereins fur Naturkunde 29: 109, pi. 9, fig. 3.

1933. Charonia gyrinoides: Bayer, Zool. Meded. Leiden 16: 55 (in part).

1938. Tritonium nodifer : Pallary, J. Conch. Paris 82: 30. 1949. Charonia lampas: Kisch, J. Conch. Lond. 23: 37; 84.

1950. Charonia nodifera: Nickles, Manuel Ouest-Africains 2: 87, fig. 134.

1952. Charonia lampas: Kisch, J. Conch. Lond. 23; 266.

1954. Charonia gyrinoides: Bellatante, J. Conch. Paris 94: 71.

1962. Charonia nodifera: Abbott, Sea Shells of the World: 68, lower left fig.

Has large nodules at periphery, similar to those of C. lampas sauliae from Japan; primary spiral cords broad and low, usually only one or two low fine interstitial threads. Many rather strong secondary spirals on shoulder. Early whorls entirely covered with many fine secondary spirals over knobs, primary spirals and interstices, and on some specimens there are traces of fine spirals over adult whorls. Inner lip smooth for almost all of its length, sometimes having a few weak plicae at top of anterior canal. Colour pattern generally bright, consisting of many dark brown splashes on a medium brown, reddish brown or fawn background; similar to that of C. lampas sauliae and C. lampas capax.

The present geographic range of the subspecies is from the islands of the English Channel to Angola (exact termination unknown), and throughout the Mediterranean Sea. Kisch (1949 a, 1949 b, 1952) recorded that it is abundant at times in the Baie de Saint-Jean-de-Luz, on the Mediterranean coast of France. Pallary (1900: 293) recorded that it was common in the littoral of Oran, Algeria, specimens reaching 38.5 by 20cms. Reeve (1844) makes the following statement: “The Triton nodiferus is a common inhabitant of the Mediterranean: having lately received upwards of sixty specimens collected by a gentleman during a short residence at Messina, I can fully testify its abundance, and Philippi mentions that certain portions of the animal are esteemed as delicious (though probably tough) eating by the Neapolitan fishermen.” The form is apparently abundant in the western Mediterranean. However, Nickles (1950: 87) stated that it is rare from Mauritania to Angola, and Pallary (1938: 30) recorded that it is very rare in the eastern Mediterranean; he knew of it only from Lattaquie and Beirut, in the Lebanon, within the area of his study. Tomlin (1944) discussed the occurrence of the subspecies at Guernsey, Channel Islands. It appears that there are very few specimens known from this locality, which seems to be the extreme northern extent of the range of the form. Thus it appears that the subspecies is common in the western Mediterranean, but is rare in the eastern Mediterranean and in the eastern Atlantic.

C. lampas lampas is sympatric with C. tritonis variegata over much of its range. It appears that C. tritonis variegata is much the less common of the two over most of the area of overlap, while it is the more common of the two (by a slight margin—both are rare) in the eastern Mediterranean. It seems likely that the two forms occupy very similar ecological niches and are partially mutually exclusive.

C. lampas lampas is the oldest known form of Charonia s.str. Small, strongly sculptured specimens that are indistinguishable from juveniles of C. lampas lampas have been recorded under many names ( gyrinoides Brocchi, ventricosum and crassum of Grateloup, ranellaeformae Sismonda, and several of the names given to Recent specimens) from the Oligocene of many localities throughout Europe, and from the Miocene of France and Italy, and undoubted specimens of lampas are known from the Upper Miocene and Pliocene of Piedmont, Italy (Bellardi, 1873: 208) and from the Pleistocene of Morocco (Nickles, 1950: 87). The species appears to have arisen in southern Europe in about the Oligocene, and spread from there all over the world.

Dimensions; The largest specimen recorded is the one mentioned by Pallary (1900; 293), which was 385 mm high and 200 mm broad. The specimen figured by Reeve (1844) is also very large and the subspecies seems to commonly reach dimensions of the same order as C. tritonis variegata. Unfortunately, no large adults were available to the writer, whose knowledge of the subspecies is based on Reeve’s figure and on four half-grown specimens in New Zealand collections. The figured snecimen, in the New Zealand Geological Survey, is 108.8 mm high and 55.3 mm broad; one from Sardinia, in the Dominion Museum, is 127 mm high and 68mm broad. Charonia lampas pustulata (Euthyme, 1889). PI. 2, Figs. 8, 10; PI. 8, Figs. 11-14.

1848. Triton sauliae: Krauss, Die Sudafrikanischen Mollusken: 148 (not of Reeve, 1844).

1886. Triton nodifer: Watson, “Challenger” Rep. Zool. 15: 389 (in part).

1889. Tritonium pustulata, with vars. minor and varicosa Euthyme, Bull. Soc. malac. France 6: 273, pi. 6, figs. 3, 4.

1892. Triton nodifer: Sowerby, Marine Shells of South Africa: 8 (not of Lamarck, 1822).

1915. Nyctilochus alfredensis Bartsch, Smithsonian Inst. Bull. 91: 94, pi. 4, fig. 4 (juvenile).

1932. Nyctilochus alfredensis: Turton, The Marine Shells of Port Alfred: 11, pi. 24, fig. 804.

1933. Charonia pustulata and alfredensis: Bayer, Zool. Meded. Leiden 16: 56, 57.

1951. Eugyrina pustulata: Barnard, Beginner’s Guide to South African Shells: 86, pi. 10, figs. 9, 10.

1954. Charonia alfredensis and pustulata: Bellatante, J. Conch. Paris 94: 71, 72

1962. Charonia pustulata: Abbott, Sea Shells of the World; 68, lower right fig.

1963. Charonia pustulata: Barnard, Ann. Sth. Afr. Mus. 47: 25, fig. 2e (radula) (with further synonymy).

1964. Charonia pustulata: Kennelly, Marine Shells of Southern Africa: 67, pi. 15, fig. 76.

1966. Charonia pustulata: Kennelly, Ann. Cape Prov. Mus. 5: 163, pis. 1 and 2.

Has thickest shell and largest nodules of all members of the lampas group. Nodules usually markedly compressed, and nodule on each varix very prominent. Most adults bear weak, rounded, broad, pale plicae over whole length of slightly darker inner lip; plicae very prominent on some juveniles. Teeth inside outer lip more prominent than in other subspecies. Shoulder and spiral interstices of some young specimens virtually smooth, bearing only one or two narrow, ill-defined threads, and a specimen in this condition was described as Nyctilochus alfredensis by Bartsch. Adults have several rather strong shoulder spirals, and many fine secondary spirals between narrow primary cords on body whorl. Colour more distinctive than in any other subspecies, a rather dull brown with darker brown markings, the whole suffused with a purplish or bluish tinge, notably around aperture and at top of spire. A few specimens are largely a bright orange-red, without purple tinge.

C. lampas pustulata is thus the most distinctive of the lampas group, resembling lampas rubicunda in its relatively prominent secondary spiral sculpture (which, however, is not as strong as in rubicunda) but differing in the much larger nodules, the purplish colour and the relatively very well developed plicae on the inner lip.

A large series of C. lampas pustulata from East London, presented to the writer by Mr D. H. Kennedy, shows great variation in size of the nodules. Young specimens, about 100 mm high, may have no nodules at all, or anything up to the massive knobs usually seen on adults. Most of the adults are very broad and squat, with a rather short spire and strongly projecting shoulders, and are more similar in shape to New South Wales specimens of C. lampas ruhicunda than any other specimens seen by the writer. Throughout the series there are occasional specimens of the red form, showing the same variation in shape and nodular development as the more usual purplish form. Kennedy (1966) has previously commented on the variation of this subspecies, with special reference to the red form. The red form appears to constitute about 5-10 per cent of most local populations of C. lampas pustulata, and could wed be due to the effects of a single recessive gene.

Charonia lampas pustulata is found only on the southern coast of South Africa, east of the Gape of Good Hope. Kennedy (1964: 67) gives the range as from False Bay, Cape of Good Hope, to Natal. There is thus a considerable gap on the west coast of Africa between the southern limit of C. lampas lampas and the western limit of C. lampas pustulata.

Fossils: “Pleistocene-Recent raised beach little Brak River (Mossel Bay)” (Barnard, 1963: 26),

Dimensions (in mm) : height diameter Port Alfred, W. J. Paul colln. 180 85 Igoda, East London 161 101 Hickman’s River, East London 169 103 Nthlonyana, Transkei 88.2 44.5 Nthlonyana, Transkei 87.1 51.7

Charonia lampas sauliae (Reeve, 1844). PI. 3, Figs. 15-17.

1844. Triton Sauliae Reeve, Conch. Icon. 2, Triton : pi. 5, figs. 17a, 17b.

1844. Triton Sauliae: Reeve, Proc. zool. Soc. Lond. 1844: 112.

1871. Triton Sauliae: Lischke, Japanische Meeres-Conchylien 1: 45.

1881. Triton nodiferus: Tryon, Man. Conch. 3: 10 (in part; pi. 3, fig. 17 only).

1882. Triton nodiferum: Dunker, Index Moll. Maris Japonici: 27 (not of Lamarck, 1822).

1886. Triton nodifer: Watson, “Challenger” Rep. Zool. 15; 389 (in part).

1933. Charonia gyrinoides var. sauliae: Bayer, Zool. Meded. Leiden 16: 56.

1936. Charonia lampas sauliae: Hirase, A Collection of Japanese Shells; 66, pi. 96, fig. 1.

1951. Charonia sauliae: Taki, An 111. Handbook of Shells in Nat. Colours from the Japanese Is., etc.: pi. 96, fig. 1.

1952. Tritonalia sauliae: Kuroda and Habe, Checklist Bibliogr. Mar. Moll. Japan: 92.

1954. Charonia gyrinoides var. Sauliae: Bellatante, J. Conch. Paris 94: 71.

1955. Tritonalia sauliae: Kira, Coloured 111. Shells of Japan, ed. 1; 43, pi. 21, fig. 12.

1961. Charonia sauliae: Kira, Coloured 111. Shells of Japan, ed. 2: 63, pi. 21, fig. 11.

1961. Charonia sauliae macilenta Kuroda and Habe, in Habe, Coloured 111. Shells of Japan 2; 46; app., p. 17; pi. 23, fig. 10.

1962. Charonia sauliae: Kira, Shells of the Western Pacific in Colour 1: 56, pi. 22, fig. 11.

1964. Chelonia [sic] sauliae macilenta: Habe, Shells of the Western Pacific in Colour 2: 75, pi. 23, fig. 10.

Has rounded peripheral and lower nodules almost as large as those of C. lampas pustulata, many fine interstitial spiral threads between narrow primary cords, and strong shoulder spirals. As in C. lampas lampas early whorls are sculptured with fine spirals over all other sculpture, and in some specimens rather strong secondary spirals cover primary spirals of adult whorls. Inner lip generally smooth for all of its length, sometimes bearing weak plicae over lower portion; in this respect C. lampas sauliae is similar to C. lampas lampas, lampas capax and lampas ruhicunda. Colour pattern

generally bright, as in C. lampas lampas, but has a pale-coloured zone over third and fourth primary spiral cords below shoulder, embracing both spirals and their interstitial area.

C. lampas sauliae is thus close to C. lampas lampas and C. lampas capax but differs in the details of colouration and in having narrow spiral cords with many fine interstitial threads, whereas the other two subspecies have broad spiral cords with only one to three fine interstitial threads. The subspecies is easily distinguished from C. lampas rubicunda, in which the many secondary spirals are coarse and prominent and there are almost no nodules, and from C. lampas pustulata, in which the colour pattern is much duller, the secondary spiral sculpture somewhat more prominent, the nodules a little larger in extreme specimens, and the plicae of the inner lip more prominent.

Kuroda and Habe, in Habe (1961: app., p. 17), named a tall, pale, thin-shelled, deep water form of sauliae as C. sauliae macilenta, but as noted in the introduction there appear to be no genetic differences between shallow water and deep water shells from within any one region, and further detailed collecting from a variety of depths will undoubtedly show that sauliae and macilenta intergrade completely and are part of one subspecies.

The geographic range of C. lampas sauliae is stated by Kira (1962: 56) to be: “South of Honshu, at 5-10 fathoms [9-18m] depth”; no southern limit is given, and I have not been able to find a statement of the southern limit of the subspecies, but there are no records from anywhere south of the main islands of Japan. Reeve (1844: expl. to pi. 5, fig. 17) gave the Philippine Islands as the type locality of Triton sauliae, but it seems highly likely that the holotype is a wrongly localised Japanese shell. Habe (1964: 75) recorded deep water specimens as “Rather commonly dredged from 150-200 m from Kii Peninsula, Honshu, and Tosa Bay, Shikoku ”.

Fossils of Charonia were not recorded from Japan by Hatai and Nisiyama (1952), and I have seen no records in later references.

Dimensions: the largest specimen I have seen (figured here), in the Powell Collection, Auckland Museum, is 245 mm high and 117 mm in diameter. A smaller specimen, in the New Zealand Geological Survey, from off Kii, Japan, is 155 mm high and 73mm in diameter.

Charonia lampas rubicunda (Perry, 1811). PI. 3, Fig. 13; PI. 4, Figs. 18-23.

1811. Septa rubicunda Perry, Conchology: pi. 14, fig. 4.

1822. Triton australe Lamarck, Animaux sans Vertebres 7: 179 (refers to Chemnitz, vol. 2, pi. 194, figs. 1867, 1868).

1844. Triton australe : Reeve, Conch. Icon. 2, Triton : pi. 4, fig. 12a; pi. 5, fig. 12b.

1852. Tritonium australe : H. and A. Adams, Genera of Recent Mollusca 1: 102.

1881. Triton nodiferus: Tryon, Man. Conch. 3: 10 (in part; pi. 4, fig. 3 only).

? 1908. Lotorium rubicundum: Moss, The Beautiful Shells of New Zealand: 19, pi. 3, lower fig.

1914. Charonia lampas var. euclia Hedley, Zool. Res. “Endeavour” 2: 65, pi. 8, fig. 1.

1915. Charonia lampas: Iredale, Trans. N.Z. Inst. 47(1): 458 (in part).

1924. Septa rubicunda: Bucknill, Sea Shells of New Zealand: 51, pi. 4, fig. 3.

1929. Charonia euclia instructa Iredale, Rec. Aust. Mus. 17: 172, pi. 41, fig. 5.

1933. Charonia gyrinoides rubicunda : Bayer, Zool. Meded. Leiden 16: 55 (in part).

1933. Charonia cf. capax : Powell, Trans. N.Z. Inst. 63: 161 (not of Finlay, 1927).

1937. Charonia capax: Powell, Shellfish of New Zealand: pi. 14, fig. 10.

1945. Charonia rubicunda : Cotton, Trans. R. Soc. S. Aust. 69: 257.

1945. Charonia euclia : Cotton, Trans. R. Soc. S. Aust. 69: 257.

1952. Charonia rubicunda: Powell, Rec. Auckland Inst. Mus. 4(3) : 175.

1954. Charonia gyrinoides var rubicunda: Bellatante, J. Conch. Paris 94; 71 (in part).

1957. Charonia powelli Cotton, Rec. Sth. Aust. Mus. 13: 120, pi. 6, lower fig.

1957. Charonia rubicunda, powelli, euclia and instructa: Cotton, Malac. Soc. Aust. publ. 4: 3, figs. 15, 16.

1959. Charonia powelli and euclia: Cotton, South Australian Mollusca, Archaeogastropoda: 371.

1962. Charonia rubicunda: Powell, Shells of New Zealand, ed. 4: pi. 14, fig. 10.

1962. Charonia euclia instructa and C. rubicunda: Iredale and McMichael, Aust. Mus. Mem. 11:54.

1962. Charonia rubicunda: MacPherson and Gabriel, Marine Molluscs of Victoria: 164, fig. 196.

1966. Charonia rubicunda: Hodgkin, Kendrick, Marsh and Slack-Smith, Western Australian Naturalist’s Club Handbook 9: 39, pi. 14, fig. 2.

One of the most distinctive subspecies in the genus. Colour typically red and pink. Spire relatively short. Nodules very low or absent. Spiral sculpture of narrow primary cords with many very prominent secondary cords between primaries and over shoulder; primary cords often almost indistinguishable from secondaries, so that whole shell is covered with prominent narrow spiral cords. Inner lip smooth for most of its height, often bearing weak plicae near base of columella.

As stated above, I do not consider that there is any genetic distinction between shallow water and deep water forms of Charonia from any one area, such as C. rubicunda and C. euclia instructa from New South Wales. This explains part of the complex synonymy of the subspecies, but the question of the forms named C. euclia and C. powelli is more involved. The form described in the diagnosis is the most extreme form of rubicunda, from the littoral of New South Wales and southern Queensland. It changes progressively out into deeper water in New South Wales and in shallow water to the south, becoming taller, paler in colour, and having weaker secondary spirals and stronger shoulder nodules. This change continues along the southern coast of Australia, so that while Victorian shells are clearly pink specimens of rubicunda, those from the South Australian Bight (type locality of powelli) and southern Western Australia (type locality of euclia) have reduced secondary spirals and have been ranked as separate species. These specimens have a more brownish colour than eastern Australian ones, and in some ways resemble New Zealand specimens of C. lampas capax; however, all Australian specimens have stronger secondary spirals than New Zealand ones (apart from the occasional New Zealand specimens of rubicunda ). The gradual change around south-eastern Australia appears to be a rather imperfect dine, apparently controlled by one-way transport of larvae rather than by any physical features of the environment. It is concluded that only one form of Charonia of the lampas group lives in Australia, and all the names are here synonymised with the earliest one, rubicunda Perry.

The original reason for raising C. euclia to a full species, i.e., that no shallowwater shells were known in southern Western Australia, was questionable in the first place, and is now known to be incorrect. Cotton (1945: 257) gave three localities for littoral specimens of rubicunda and two for littoral specimens of euclia in South Australia, and four localities for rubicunda and three for euclia in southern Western Australia, Hodgkin et al. (1966) recorded C. rubicunda as ranging from New South Wales to Jurien Bay, on the west coast of southern Western Australia, and the specimen they figured is inseparable from rubicunda. The known geographic range of C. lampas rubicunda in Australia is thus from southern Queensland to southern Western Australia, and the depth range includes most or all of the continental shelf.

There is still a further complication in the picture. In northern New Zealand waters (mainly in Manukau Harbour, Hauraki Gulf and the Bay of Plenty) occato result from transport of larvae across the Tasman Sea, which presents a relatively sional littoral specimens of what appear to be true rubicunda occur. They seem permeable barrier to Cymatiidae. About 30 per cent of northern New Zealand specimens examined, both littoral and trawled, show varying degrees of rubicunda

influence in their characters; i.e., some northern shells of the capax type have more numerous secondary spirals and pinker colouration than most members of the population. This is interpreted as interbreeding of native capax with specimens of ruhicunda that have arrived from Australia as larvae. This leads to a highly unusual situation, brought about by the extreme vagility of the larvae of Gymatiidae, where two geographic subspecies are occasionally sympatric, but not necessarily isolated reproductively, and it is likely that some workers will prefer to regard ruhicunda and capax as synonyms on this evidence. Whatever decision is arrived at regarding nomenclature, it appears that dispersal barriers between the two forms have recently broken down and the forms are presently re-merging as one population. The nomenclature to be used for such a situation is difficult to decide upon, and until the genetics, dispersal and anatomy of the forms involved have been investigated in considerable detail it seems best to follow the more objective approach and maintain ruhicunda and capax as separate subspecies.

The first specimens of the ruhicunda type known to have been collected in New Zealand are the six living specimens found at the old pilot wharf, Mount Maunganui, by Dr C. E. Bucknill in the early 1920’5. The most brightly coloured of these, figured by Powell (1962: pi. 14, fig. 10) and herein, is exactly comparable in all features with New South Wales littoral specimens of ruhicunda. The other specimens of Bucknill’s series seen by the writer (in the Auckland Museum and the New Zealand Geological Survey) also appear to be faded specimens of true ruhicunda. Two other specimens examined by the writer (one from a small island off Kawau Island, Hauraki Gulf, in the collection of Mrs A, Edwards of Warkworth, and one from Waihi Beach, Bay of Plenty, in the Ponder Colin., Dominion Museum) are exactly comparable with New South Wales shells, and several such specimens are reported from Manukau Plarbour, Auckland, in various numbers of the Bulletin of the Conchology Section, Auckland Institute and Museum, and from Tairua, near Mercury Bay, by Powell (1952: 175).

The specimen on which Hutton (1878: 18) and Suter (1913: 303) based their records of Charonia from the Chatham Islands is lodged in the Otago Museum, where it has been examined by the writer. It is a small, squat, faded, pale pink specimen of C. lampas ruhicunda, so closely identical to faded specimens from near Sydney that there seems little doubt that it is a wrongly localised Australian shell. Powell (1933 b) and Finlay (1928) were unable to confirm the occurrence of Charonia at the Ghathams, and although it seems quite possible that C. lampas capax occurs there, no valid records are yet available.

True Charonia is not known fossil in Australia. Powell (1933 a: 166) recorded a specimen from the Abattoirs Bore, Adelaide (Pliocene), as Charonia n.sp. ancestral to ruhicunda, but examination of the specimen (in the Finlay Colin., Auckland Museum) showed that it is a specimen of Vernotriton hassi (Angas).

Dimensions: C. lampas ruhicunda does not appear to reach a very large size. The largest Australian specimen I have seen, figured herein and sent on loan from the National Museum of Victoria, is 155 mm high and 92mm in diameter. The specimen (originally identified as powelli ) from South Australia figured herein, in the Dominion Museum, is 144.2 mm high and 73.3 mm in diameter, and the specimen from Mount Maunganui, Tauranga, New Zealand, in the Auckland Museum, is 140 mm high and 83mm in diameter.

Charonia lampas capax Finlay, 1927. PI. 5, Figs. 24-29.

1810. Triton tritonis: Montfort, Gonchyliologie Systematique 2: 587, unnumbered fig.; “ un jeune individu de la Nouvelle Zelande ” (in part, not Mur ex tritonis Linnaeus, 1758).

1873. Triton australe: Hutton, Cat. Marine Moll. N.Z.: 13 (not Lamarck, 1822).

1878. Tritonium australe: Hutton, J. Conch. Paris 26: 18 (in part).

1880. Tritonium australis: Hutton, Manual N.Z. Mollusca: 63.

1885. Triton nodiferus : Hutton, Proc. Linn. Soc. N.S.W. (1)9: 932 (in part not of Lamarck, 1822).

1904. Lotorium rubicundum: Hutton, Index Faunae Novae Zelandiae: 75 (not of Perry, 1811).

1910. Septa ruhicunda : Iredale, Proc. malac. Soc. Lond. 9: 71.

1913. Septa ruhicunda: Suter, Manual N.Z. Mollusca: 303, pi. 1, fig. 33; pi. 43, fig. 1 (in part).

1915. Charonia lampas: Iredale, Trans. N.Z. Inst. 47: 458 (in part not Murex lampas Linnaeus, 1758).

1915. Charonia lampas: Oliver, Trans. N.Z. Inst. 47: 527.

1927. Charonia capax Finlay, Trans. N.Z. Inst. 57: 397, pi. 20, fig. 67.

1927. Charonia capax euclioides Finlay, Trans. N.Z. Inst. 57: 398, pi. 20, fig. 68.

1928. Charonia capax: Finlay, Trans. N.Z. Inst. 59: 246.

1933. Charonia gyrinoides ruhicunda: Bayer, Zool. Meded. Leiden 16: 55 (in part).

1933. Charonia capax euclioides: Powell, Trans. N.Z. Inst. 63: 161.

1937. Charonia capax: Iredale, Rec. Aust. Mus. 20: 106.

1952. Charonia capax: Powell, Rec. Auckland Inst. Mus. 4(3): 175,

1954. Charonia gyrinoides var. ruhicunda: Bellatante, J. Conch. Paris 94: 71 (in part).

1962, Charonia capax: Powell, Shells of N.Z., ed. 4: pi. 14, fig. 9.

Specimens of Charonia lampas from New Zealand (apart from the occasional specimens of C. lampas ruhicunda, mentioned above) closely resemble C. lampas lampas and C. lampas sauliae in having almost smooth inner lips with a few weak plicae over the anterior end, moderate-sized nodules over body and spire whorls, a few fine secondary spiral threads, and a colour pattern of dark brown splashes on a background of pale to medium yellowish brown. C. lampas capax has broad primary spirals with two or three broad secondary spirals in the interstices, and has smaller nodules than in C. lampas lampas and C. lampas sauliae. As noted under C. lampas ruhicunda, about 30 per cent of northern specimens have stronger and more numerous secondary spiral threads than others, apparently as a result of interbreeding of capax and ruhicunda. C. lampax capax differs from C. lampas ruhicunda in its paler and more brownish colour, its weaker and less numerous secondary spiral threads, and its larger nodules, and from C. lampas pustulata in its more brownish colour, its less numerous secondary spiral threads, its considerably smaller nodules, and in the absence of plicae over most of the inner lip.

Charonia lampas capax is moderately common intertidally in northern Auckland as far south as Manukau Harbour on the west coast of New Zealand, and as far south as Tauranga Harbour on the east coast. It is taken commonly by skin divers and trawlers in depths of up to 90m within the same region, and less frequently in depths of up to about 130 m around the rest of New Zealand, as far south as Foveaux Strait. A few specimens have been taken by the Foveaux Strait oyster dredges, and a few are reported from crayfish pots from the northern part of Stewart Island. As observed in Australia and Japan, specimens from deep water have progressively taller spires as depth increases; one trawled off Otago in 110-130 m, in the Dominion Museum, is the tallest New Zealand specimen examined by the writer.

Ten adult specimens of Charonia from the Kermadec Islands in the Dominion Museum have the colour of C. lampas capax, and have rather strong and numerous secondary spirals as in northern New Zealand capax-ruhicunda hybrids. The single young live-collected specimen is clearly referable to C. lampas capax. Thus the situation seems to be similar to that in New Zealand, where an original capax population is apparently being modified by an influx of ruhicunda larvae from Australia, and Kermadec specimens are here referred to C. lampas capax.

Geographically C. lampas capax ranges from the Kermadec Islands, throughout the main islands of New Zealand to northern Stewart Island. A record from the Chatham Islands requires substantiation.

Fossils of C. lampas capax have been seen from: dunes behind Houhora Heads, Northland (Holocene) ; dunes behind Tokerau Beach, Doubtless Bay (Holocene); 2ft below water level, inside of bar across mouth of Lake McKerrow, southern Westland (Holocene; recorded by Beu in Wellman and Wilson, 1964: 714); and Te Piki, Gape Runaway (uppermost Castlecliffian, lower Pleistocene; recorded by Powell, 1934: 264).

Dimensions: the largest New Zealand specimen seen, in the collection of Mr Noel Peterson of Tauranga, taken in a crayfish pot in 27m off Astrolabe Reef, Motiti Island, Bay of Plenty, is 263 mm high and 141 mm in diameter. The figured specimen from Manukau Harbour is 213 mm high and 100 mm in diameter; and that from 110-130 m off Otago is 188 mm high and 89mm in diameter.

Discussion

Ecology of Charonia

In New Zealand C. lampas capax is found on exposed rocky coasts and in rocky areas in the outer parts of large harbours in the north. It is probably more common on islands off the coast (e.g., Kawau, Mayor, and Motiti islands) than on the mainland. Around rocks it has been taken in depths of from 0 to 27m. It usually hides in deep crevices between weed-covered rocks, and shelters under ledges in areas of flat-lying Tertiary rock. C. lampas capax is considerably more common in deep than in shallow water. It is commonly taken in trawls or in crayfish pots in northern New Zealand in depths of about 20 to 100 m, usually on rock, sand or shelly material, and rarely on silt or clay. The animals I have seen from shallow water shells were cream mottled with various shades of light to dark red and with orange and black bands on the tenticles; animals from trawled shells had uniform cream bodies, the only marked colouration being the orange and black tentacle bands. It is likely that there is a gradation in the colour of the animal parallel to that of the shell, as the habitat depth increases.

The few New Zealand specimens of C. lampas rubicunda have been taken in shallow rocky environments, often alongside specimens of C. lampas capax. Hodgkin et al. (1966) and MacPherson and Gabriel (1962: 164) recorded that C. lampas rubicunda lives in shallow water among weedy rocks in Australia.

Kisch (1949 a) recorded that many live specimens of C. lampas lampas had been seen in 1948 among rocks at Socoa, Baie de Saint-Jean-de-Luz, Mediterranean coast of France. Some were feeding on Holothuria forskali Delle Chiaje. He thought (1949 b) that they had recently moved up from the coralline zone to the lower littoral zone. Kisch later (1952) noted that a party of boys using goggles had collected 38 specimens at a depth of about a metre in a small area at the same locality. On June 2, 1950, at Socoa, he observed two specimens feeding on echinoids, Paracentrotus lividus. An echinoid was grasped in the gastropod’s foot and the spines and shell were removed from a small area. He suggested that the shell was removed by acid in the saliva, and gave a reference to a paper by Pelseneer (not seen) in which acidic saliva was recorded in Charonia. He also suggested that the abundance of the echinoid accounted for the abundance of Charonia lampas lampas, and it seems likely that the distribution of the mollusc is at least partly controlled by the distribution of its prey.

Clench and Turner (1957: 196) stated that C. tritonis variegata “is generally found about rocks below low water. Specimens taken from fish traps that had been placed in 60 to 120 fathoms [llO to 220m] were very much lighter in structure and somewhat smaller”. According to Abbot (1950: 79), in the Cocos-Keeling Islands C. tritonis tritonis is “ not uncommon in shallow weedy water on the east side of the lagoon. Larger individuals occur in deeper water or on the barrier reef”. Dodge (1957: footnote to pp. 169, 170) quoted Stimpson concerning C. tritonis variegata : “ I found about 30 living specimens on the reef at Tortugas,

of an apparently stunted form, being very solid and having a very heavy lip, though not over seven or eight inches in height Dodge himself collected specimens, which he implied were more normal, “ in the Bahamas, alive in sandy and grassy stations in protected water”. It appears that the ecology of C. tritonis is much the same as that of C. lampas, except that the species is frequently found on coral reefs.

According to Copland (1966), C. tritonis tritonis is an important agent in reducing the numbers of the large coral-eating “ crown-of-thorns ” starfish, Acanthaster planci (Linnaeus), a species that was illustrated and described later (Schoenberg, 1966). The starfish has an unusually large central disc, over a foot in diameter, and relatively short arms. It is reported that Charonia penetrates the skeleton of the starfish by rasping through it with its radula, but the acidic saliva reported by Kisch (1952) probably plays an important part as well.

The geographic ranges of C. lampas subspecies in the Indo-Pacific terminate more or less where they encroach on that of C. tritonis tritonis, and probably the only reason C. lampas lampas does not do so in the Atlantic is because of the rarity of C. tritonis variegata.

Evolution of Charonia

There are several small Australasian genera of the Charoniinae that may have been ancestral to Charonia. Proxicharonia Powell is a Neozelanic genus containing small, relatively smooth, distorted species, and is apparently not directly on the line to Charonia. Negyrina Iredale is more the shape of Charonia, has coarse sculpture similar to that of juveniles of Charonia, and seems likely to represent the stage of evolution that was immediately ancestral to Charonia. Vernotriton Iredale contains small, finely sculptured species, shorter than Charonia, resembling some of the smoother European Tertiary species of Sassia in their sculpture. It seems likely that Vernotriton or a similar genus was the ancestor of Negyrina, and that Negyrina was the ancestor of Charonia. Charonia first appears in the Oligocene of Europe, and it is possible that Vernotriton, Negyrina and Charonia all evolved in Europe, spread down the west coast of Africa to South Africa, and then were dispersed by the west-wind drift to Australasia.

Evolution and dispersal in Charonia

The distribution of the forms of Charonia has been outlined above, and is shown in Text-fig. 1. Of the temperate and tropical seas of the world, the only areas that are not inhabited by a subspecies of Charonia are the west coast of the Americas, the east coast of the Americas north and south of the range of C. tritonis variegata, and (somewhat doubtfully) the west coast of Africa between Angola and the Cape of Good Hope. C. tritonis is distributed throughout tjie tropical seas of the world except the west coast of the Americas, and is known fossil only in the Pliocene of Venezuela. The distribution of C. lampas is the eastern Atlantic Ocean, the Mediterranean Sea, South Africa, Australasia, and Japan. The species has a fossil record from the Oligocene in Europe, from the Upper Pleistocene in South Africa, and from the late lower Pleistocene in New Zealand. It is not known fossil or Recent in the Americas and apparently never reached there.

The evolution and dispersal of the various forms of Charonia is interpreted as follows. C. lampas arose from Negyrina or a similar genus in the Paleogene in Europe, and spread down the west coast of Africa to South Africa. It was dispersed from there by the west-wind drift to Australasia during the Lower Pleistocene, probably assisted by lengthening of larval life by the lowering of sea temperature. After becoming well established in Australasia, it moved north through the western Pacific archipelagos to Japan. At this stage all forms were probably very similar, as C. lampas lampas, C. lampas sauliae and C. lampas capax are still very similar, but partial genetic barriers were probably set up during the post-glacial immediately

following their dispersal, and geographic subspeciation probably progressed rapidly. Until recently there may have been a barrier to dispersal between Australia and New Zealand, but its nature is not understood.

The relationship of C. tritonis to C. lampas is not clear. If C. tritonis entered the Atlantic through the Panama seaway, it must have done so before the late Pliocene, as the seaway closed at that time, and the species is known fossil in the Pliocene of Venezuela. C. tritonis seems to be more advanced than C. lampas, and thus probably evolved from it, but when and where is not clear. As C. lampas did not reach the Indo-Pacific until the Pleistocene, when C. tritonis was already in occupation, it seems likely that C. lampas migrated north to Japan during a glacial phase, and as C. tritonis would have withdrawn to the warmest waters of the central western Pacific at that time, it is likely that for one reason or another ecological competition between the two species did not arise immediately. Genetic interchange between Australasian and Japanese populations of C. lampas must now be slight.

Acknowledgments

I thank Mr D. H. Kennedy, of East London, South Africa, for a generous gift of specimens of C. lampas pustulata, and the late Mrs A, C. Davis, of Orlando, Florida, for a gift of specimens of the same subspecies; many New Zealand private collectors (notably Mrs A. R. Atkinson, Mrs L. Edwards, Mr B. Tetley and Mr N. Peterson) for information on the depth and geographic distribution of C. lampas capax; and Professor P. Vella of the Geology Department, Victoria University of Wellington, and Dr G. A. Fleming of the New Zealand Geological Survey for critical comments on the manuscript.

Support was provided by a Post-graduate Scholarship from the University Grants Committee.

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