New Zealand Gastropod Molluscs of the Genus Pteropurpura Jousseaume

Transactions of the Royal Society of New Zealand : Biological Sciences, Volume 12, Issue 12, 26 May 1970, Page 133

New Zealand Gastropod Molluscs of the Genus Pteropurpura Jousseaume

A. G. Beu

By

N.Z. Geological Survey, D.S.I.R.

[Received by the Editor, 24 June 1969 1

Abstract

The group of “ Pterynotus ” laetificus Finlay is removed from Pterynotus (Muricinae) and placed in Pteropurpura (Ocenebrinae). New Zealand representatives of Pteropurpura are P. kaiparaensis (Fleming) (Lower Miocene), P. laetifica laetifica (late Oligocene to late Miocene), P. laetifica flemingi (Beu) (late Pliocene to Recent), and a new subspecies of P. laetifica from Lome, near Oamaru (Upper Eocene).

Introduction

Fleming (1962) reviewed the New Zealand members of the muricid gastropod genus Pterynotus Swainson, figuring the holotype and other specimens of P. laetificus Finlay, and ascribing the laetificus group to Pterynotus sensu stricto. He considered Pterochelus, Poropteron, Pteropurpura, and Purpurellus (all of Jousseaume, 1880) as alternative positions for P. laetificus, and referred some New Zealand shells correctly to Pterochelus; however, he was hesitant about the distinction between the Pteropurpura-Purpurellus group and Pterynotus (justifiably, as anatomical data were not available to him), and included all species of these three groups in Pterynotus sensu stricto. Since then, Yokes (1964) has reviewed supraspecific categories in the subfamilies Muricinae and “ Tritonaliinae ” (Ocenebrinae of this paper), and showed that on radular and opercular grounds Pteropurpura (of which she ranked Purpurellus a subgenus) belongs in the Ocenebrinae, whereas Pterynotus (of which Pterochelus and Poropteron are ranked as subgenera) belongs in the Muricinae. The resemblance of Pteropurpura to Pterochelus is attributed to convergence rather than to phylogenetic relationship.

Powell (1967: 192) recorded a Recent shell from northern New Zealand as Pteropurpura cf. plorator (A. Adams and Reeve), and comparison of Powell’s figures with specimens of “ Pterynotus ” laetificus Finlay showed that the two forms are very similar and apparently closely related.

Since the publication of Fleming’s paper on Pterynotus, much additional material of the laetificus group has been accumulated, largely through the collecting efforts of Mr P. A. Maxwell, New Zealand Geological Survey. These specimens add greatly to knowledge of the time ranges and morphology of P. laetificus and related

forms. Also, the New Zealand Oceanographic Institute “ North-west slope Benthos ” Cruise of October 1968 collected two further Recent specimens related to P. laetificus from approximately 480 metres, west of Ninety-Mile Beach, Northland, adding to knowledge of variation of Recent specimens. Thus a review of the taxonomic position of “ Pterynotus ” laetificus and a survey of its relatives in New Zealand seemed timely.

Taxonomy

Family MURICIDAE Swainson, 1840

Subfamily OCENEBRINAE Gossmann, 1903

Yokes (1964) used the subfamily name Tritonaliinae Korobkov, 1955, instead of the long-established and much better known Ocenebrinae. The question of Tritonalia Fleming, 1828, versus Ocenebra Gray, 1847, depends on the interpretation of Tritonalia Fleming, a name erected in a highly unsatisfactory manner in the index to Fleming’s work, and interpreted as either a new name for Triton Montfort, 1810 (i.e., the genus now called Charonia Gistel, 1847), or as a senior synonym of Ocenebra. Keen (1964) has applied to the International Commission on Zoological Nomenclature to have Tritonalia Fleming suppressed, and this seems the most suitable solution to a complex problem.

The International Code of Zoological Nomenclature (Article 40) states that, after 1960, if a nominal type-genus is rejected as a junior synonym, a family-group name based upon it is not to be changed; but in Article 40(a) it states that if a family-group name changed because of such synonymy before 1961 has won general acceptance, it is to be maintained in the interests of stability of nomenclature. It is not clear from the Code how Article 40 affects family-group names when the senior synonym is suppressed by the Commission. However, it is clear that as the name Tritonaliinae has been used only four times (Yokes, 1964: 3; Ponder, 1968: 31), it has not “won general acceptance” in place of the long-established name Ocenebrinae, and it is considered that if Keen’s application is ratified by the Commission, the family-group name based on Ocenebra Gray, 1847, should be Ocenebrinae rather than Tritonaliinae; the usage here of Ocenebrinae is nearer to maintaining the status quo (the general policy of the Commission before applications are ratified) than the usage of Tritonaliinae would be. Yokes was aware of Keen’s application (Yokes, 1964: 20, footnote), and it would have been preferable if she had used Ocenebra and Ocenebrinae rather than Tritonalia and Tritonaliinae.*

Genus Pteropurpura Jousseaume, 1880

1880. Pteropurpura Jousseaume, Le Naturaliste, Annee 2(42) : 335 (fide Yokes, 1964: 24).

1931. Centrifuga Grant and Gale, Mem. San Diego Soc. nat. Hist. 1: 706. Type species (by original designation) ; Mur ex centrifuga Hinds, 1844, Recent, western North America.

Type species (by original designation): Mur ex macropterus Deshayes, 1841, Recent, California. , 'O'

Emerson (1964) recently discussed the identity of Murex macropterus Deshayes, concluding that it was the Recent Californian species long known as " Pteronotus ” carpenteri Dali. He gave several clear figures of Murex macropterus Deshayes, including one of the holotype.

Yokes (1964: 24) commented on the generic relationships: “The shells of this group bear a striking resemblance to those of Pterynotus but the radula and the purpuroid operculum indicate that this is due to convergence rather than to close

relationship” (she retained Pterynotus in the Muricinae). “There is also a strong resemblance to the more alate members of the Ceratostoma group such as Murex foliatus, but Pteropurpura may be distinguished by the lack of the monoceroid tooth and denticulate aperture characteristic of Ceratostoma

Fleming (1962: 110) included the large, weakly sculptured, tri-varicate New Zealand Tertiary species of the “ Pterynotus ” laetificus lineage in Pterynotus sensu stricto, noting their resemblance to species included in Pteropurpura, but also noting that the type species of Pterynotus, Murex pinnatus Swainson, 1822, is an aberrant species. The members of the laetificus group have weakly dentate outer lips, lack the large monoceroid tooth of Ceratostoma, and resemble foreign species of Pteropurpura closely in shape, in their weak spiral sculpture, in their three thin, broadly expanded varices united up the shell so that it has a triangular cross-section, in lacking a posterior canal in the outer lip, and in having one or a few relatively small nodules between varices. Thus they seem referable to Pteropurpura rather than to Pterynotus, which was (correctly, in the writer’s opinion) used by Yokes (1964: pi. 2, p. 37) for such species as Murex elongatus Lightfoot (= Murex clavus Kiener). Some of the specimens of Pteropurpura macroptera (Deshayes) figured by Emerson (1964) are extremely similar to New Zealand specimens of Pteropurpura laetifica.

Pteropurpura seems to be widespread in the Tertiary rocks of the world. All the species listed by Fleming (1962: 112) as members of Pterynotus s.str. are members of Pteropurpura, and many others occur in the early and middle Tertiary of Europe and the middle and late Tertiary of North America. The genus now lives in Japan, in Australia (and probably in the western Pacific archipelagoes between these extremes), in New Zealand, in central and northern western America, and in the western Atlantic.

Of the Australian Tertiary Muricidae described by Tate (1888), Murex {Pterynotus) velificus (Tate, 1888: 95, pi. 1, fig. 8) and Murex ( Pterynotus) calvus (Tate, 1888: pi. 1, fig. 11) can definitely be referred to Pteropurpura. Most of the other species referred to “ Pterynotus ” by Tate belong in Pterochelus Jousseaume, but Murex ( Pterynotus) bifrons (Tate, 1888: 97, pi. 1, fig. 12) has many irregularly placed varices and cannot be referred with certainty to any of the established genera on the basis of Tate’s figure. Finlay (1930: 77) and Fleming (1962: 112) noted that Murex calvus Tate, 1888, was the Australian Tertiary species most closely related to P. laetifica; however, the Recent Australian Pteropurpura hednalli (Brazier) is very much more similar to P. laetifica than is P. calva, and may be phylogenetically related. The similarity is discussed further under P. laetifica laetifica.

Pteropurpura laetifica (Finlay, 1930) New Zealand Cenozoic and Recent members of Pteropurpura fall into two species; P. kaiparaensis (Fleming), discussed below, is a distinct species that may not have evolved directly from the lineage of P. laetifica. All other Upper Eocene to Recent Pteropurpura from New Zealand are here referred to three subspecies of P. laetifica (Finlay).

Pteropurpura laetifica laetifica (Finlay, 1930). PI. 1, Figs. 1-3, 5,8; PI. 2, Figs. 13—15, 18. 1930. Pteronotus (s.str.) laetificus Finlay, Trans. N.Z. Inst. 61: 76. 1931. Pteronotus n.sp. Marwick, Paleont. Bull. N.Z. geol. Surv. 13: 118, pi. 12, fig. 226. 1962. Pterynotus (s.str.) laetificus: Fleming, Trans. R. Soc. N.Z. zool. 2(14): 111, pi. 1, figs. 2-8.

Topotypes or near-topotypes of Pteropurpura laetifica, from the type, locality of the Waiauan Stage (late Middle Miocene), the Nissen shellbeds at Park Bluff, Clifden (see Fleming, Chapter 4, in Wood, 1969), are very rare. Fleming (1962:

111) considered that the type locality was probably a “ silty sandstone above the fourth [Nissen] shellbed ”, and the only other specimen known from this locality is a fragmentary spire figured by Fleming (1962: pi. 1, fig. 4). Both specimens are worn, highly incomplete, and stained yellow and orange. The holotype has a softer matrix than specimens from Nissen Shellbed No. 1, and is paler in colour, so that it must have come from higher in the sequence than Nissen 1; however, the exact locality is not known as yet. Mr P. A. Maxwell and the writer recently collected a fragmentary spire and two large fragments of variceal flanges of Pteropurpura from Nissen Shellbed No. 1, the basal unit of the Waiauan Stage at Clifden; the variceal fragments represent the stratigraphically nearest ones to the type locality of P. laetifica, and presumably show what those of topotypes would be like. They are unique among all New Zealand Pteropurpura in having a prominent spine formed at the shoulder by a broad, shallow, open, posterior canal. The canal is not deep and semitubular to tubular as in Pterochelus, and there seems no reason why shells bearing it should not be retained in Pteropurpura. However, the restriction of this character to Waiauan specimens suggests the possibility that P. laetifica may be distinct from all other New Zealand populations of Pteropurpura. In view of the relatively great variation in almost all features seen in New Zealand populations of Pteropurpura, this possibility is discounted here; further Waiauan material must be collected before the situation will become clear.

The availability of a very much larger number of considerably more complete specimens of P. laetifica laetifica from a much greater range of ages and lithofacies than those available to Fleming (see list of localities, below) has enabled the writer to obtain a clearer picture of the adult shell morphology and of the range of variation of the subspecies than Fleming could have deduced. It now appears that almost all the adult material available to Fleming was worn and its varices badly damaged before fossilisation. The extremely well-preserved specimen from Trig. Z, Otiake, Waitaki Valley (Waitakian) figured here (PI. 1, Figs. 1,3) has moderately prominent, ill-defined, widely spaced spiral cords over the whole shell surface, the spirals becoming more prominent over the outer part of the variceal flanges than they are on the rest of the shell, and causing the outer edges of the varices to be fluted and sometimes spinose. The spire is moderately tall, the siphonal canal long and open, and the outer lip dentate and thickened as described by Fleming. The variceal flanges are expanded considerably more widely over the shoulder and periphery than they are lower on the whorls in all specimens seen that have varices well preserved. Young shells from Calamity Point, Clifden (Altonian) in Auckland University Geology Department and from the north bank at Clifden (Clifdenian) in Victoria University Geology Department have the same tall spires, moderately prominent spirals, and single nodule in each intervariceal space as the one from Trig. Z, and the specimen from the north bank at Clifden (figured here, PI. 2, Fig. 13) has one varix complete on one whorl, demonstrating that juvenile varices are expanded more on the shoulder than elsewhere, as in adult shells.

A large spire from Upper Tengawai River near its junction with Trap Creek, South Canterbury (Waitakian), figured here (PI. 1, Fig. 8), is relatively shorter and broader than the Trig. Z specimen, and its spirals become weaker over the varices rather than more prominent. The edges of the unusually broad variceal flanges are thus smooth and regular, rather than fluted and spinose. It is possible that this specimen represents a new species, but other less complete specimens from many localities are intermediate between these two extremes in all features, and it is concluded that they fall within the range of variation of one species. The varices of succeeding whorls on the specimen from Tengawai River overlap those on whorls above, causing a thickened area at their junctions and a ridge on the variceal flange at each junction.

Finlay (1930; 77) and Fleming (1962: 112) recorded the Target Gully (Awamoan) form of Pteropurpura as a distinctive relative of P. laetifica. Fleming

stated that the only specimen then available (presently lost) was a damaged juvenile, originally about 7mm high, that was more slender and had more prominent, more narrowly elongated nodules than in P. laetifica s.str. The present material shows considerable variation in spire height and nodule shape, and shows that apices and juvenile specimens are often narrower than later whorls. Also, a specimen collected at Awamoa Creek, Oamaru, by the writer and Mr P. A. Maxwell from beds of similar age to that of the Target Gully Shellbed, belongs in P. laetifica laetifica. Thus the Target Gully specimen is here referred to the nominate subspecies.

Pteropurpura hednalli (Brazier, 1877), a rare species from the north coast of Australia, seems to be the only Recent Australian species referable to Pteropurpura. Two specimens in the collection of Mr W. Paul, of Wellington, and two large, slightly beach-worn ones in the New Zealand Geological Survey, all from Port Keats, Northern Territory, have been examined in this study. They have almost identical spiral sculpture, intervariceal nodules, ridges across the variceal flanges where succeeding varices overlap, and thickened dentate outer lips to those of P. laetifica laetifica (as the latter is here interpreted), and show the shape and general appearance that a complete specimen of P. laetifica might be expected to have. Indeed, the only features that differentiate the two forms consistently are that the variceal flanges of P. bednalli are considerably more strongly fluted, due to much more pronounced increase in strength of the spirals over the varices than in P. laetifica, and that the varices of P. bednalli are of approximately equal height all down the shell, and not consistently more markedly expanded on the shoulder as in P. laetifica. The resemblance between the two species is so great as to suggest direct phylogenetic relationship. The Eocene to Recent P. laetifica could well have been the direct ancestor of P. bednalli, in which case laetifica could be treated as a subspecies of bednalli; however, the geographic separation is relatively large, and the apparent relationship may be due to lack of knowledge of Australian Tertiary and Recent Pteropurpura. Therefore it seems best to maintain laetifica and bednalli as full species at present. The largest and most complete of the four specimens of P. bednalli available to me, in the New Zealand Geological Survey, is figured here (PI. 1, Figs. 7,9).

From the proportions of the shell and body whorl in the largest specimen of P. bednalli, and the size of the body whorl of the holotype of P. laetifica, it is estimated that the latter, when complete, and with all variceal flanges complete, would have been approximately 107 mm high, and 73mm in diameter across the two ventral varices.

Dimensions of P. laetifica laetifica (in mm) :

height diameter Holotype 48.5 40.0 G 59516, Trig. Z, Otiake 50.1 31.7 G 59569, Upper Tengawai River 35.2 33.4 G 59781, Parengarenga Harbour (juv.) 11.3 6.3 V 572, North Bank, Clifden (young shell) 20.2 12.2 G 55623, Alton Mill, near Clifden 59.2 30.0 G 510342, near Te Araroa, East Cape 56.2 28.3

Localities: Waitakian: G 59516, Trig. Z, Otiake, Waitaki Valley, North Otago, coll. T. A. Darragh and P. A. Maxwell, Feb., 1968; G 59569, Upper Tengawai River near its junction with Trap Creek, South Canterbury, coll. T. A. Darragh and P. A. Maxwell, Feb., 1968; second fragmentary specimen from same locality coll. A. G. Beu and P. A. Maxwell, Oct., 1968.

Otaian : G 54795, Blue Cliffs, South Canterbury, coll. A. G. Beu and P. A. Maxwell, Oct., 1968, small spire and fragment of a large outer lip; G 55850, N9l/518, grid ref. 215393, small tributary of Awakino River, Awakino Gorge, North Taranaki, coll. N. de B. Hornibrook, D. Rear and J. C. Schofield, Feb. 8, 1953 (Otaian-Awamoan).

Awamoan: AM7970, Target Gully, Oamaru, coll. C. R. Laws, H. J. Finlay Collection, Auckland Institute and Museum; G 59520, spillway of earth dam 200yds up Awamoa Creek from its mouth, coll. A. G. Beu and P. A. Maxwell, Oct., 1968; G 59871, Te Pokere, north shore of Parengarenga Harbour, Northland, coll. G. J. Wilson and P. A. Maxwell, Oct., 1967, one juvenile; G 59872, Te Pokere, Parengarenga Harbour, coll. G. J. Wilson and P. A. Maxwell, Oct., 1967, one young shell; also one juvenile coll. A. G. Beu and P. A. Maxwell, March, 1969.

Altonian : 5167/637, Calamity Point, Glifden, Southland, coll. J. A. Grant-Mackie and P. F. Ballance, Auckland University Geology Department; G 510365, Long Beach, Glifden, Southland, A. G. Beu and P. A. Maxwell, Feb., 1969.

Clifdenian : G 52155, North Bank, Glifden, Southland, coll. J. Marwick and R. W. Willett; V 572, North Bank, Glifden, Southland, coll. J. Fade, J. Kennett and P. Vella, Victoria University Geology Department. Lillburnian: G 52939, Lill Sand (“Glifden band 7”), Glifden, Southland, coll. J. Marwick and R. W. Willett.

Waiauan: Holotype (incomplete very large body whorl, figured by Fleming, 1962: pi. 1, figs. 7,8), “Glifden 7c, close to band 8” (Finlay, 1930), probably from “a silty sandstone above the fourth [Nissen] shellbed ”, Park Bluff, Glifden (Fleming, 1962: 111); G 57704, probable topotype, silty sandstone above fourth Nissen Shellbed, Park Bluff, Glifden, coll. G. A. Fleming et al. (figured Fleming, 1962: pi. 1, fig. 4); AM8033, Glifden Band 8, Laws Colin., Auckland Institute and Museum; GS 10343, Nissen Shellbed No. 1, Park Bluff, Glifden, coll. A. G. Beu and P. A. Maxwell, Feb., 1969; G 55623, stream bank half mile south of Alton Mill, Alton S.D., near Glifden, Southland, coll. B. L. Wood (figured Fleming, 1962: pi. 1, fig. 6).

Tongaporutuan : G 51322, near ridge, 126 ch ESE of Trig. D, Block 6, Waikohu S.D., north of Gisborne (Marwick, 1931: 42, 118, pi. 12, fig. 226; Fleming, 1962: pi. 1, fig. 5).

Kapitean: N63/936552, platform at end of small beach, Pohauturoa, East Cape, coll. G. G. H. Chaproniere, April, 1967, Auckland University Geology Department; GS 10342, shore platform one mile east of Te Araroa, near East Cape, coll. A. G. Beu and P. A. Maxwell, Nov., 1966.

Holotype in Finlay Collection, Auckland Institute and Museum; figured juvenile from North Bank, Glifden, in Victoria University Geology Department (VM885); all other figured specimens of Marwick (1931), Fleming (1962), and this paper in New Zealand Geological Survey.

Time Range: Waitakian (late Oligocene or basal Miocene) to Kapitean (uppermost Miocene).

Pteropurpura laetifica flemingi (Beu, 1967). PI. 2, Figs. 16, 17, 19-26 1967. Pterynotus ( Pterynotus ) flemingi Beu, Trans. R. Soc. N.Z. geol. 5(3): 102, pi. 1, fig. 9. 1967. Pteropurpura cf. plorator (A. Adams and Reeve) : Powell, Rec. Auckland Inst. Mus. 6(3): 192, pi. 37, figs. 2-4 (not P. plorator A. Adams and Reeve, 1850).

Beu (1967: 102) described Pterynotus flemingi on the basis of one well-preserved but broken, extremely squat shell (the holotype) and one very poorly-preserved, broken, taller shell, both collected by Mr P. Wellman from Mangapanian siltstone east of Whangaimoana, Palliser Bay, South Wairarapa. Since then Powell (1967: 192) has recorded a living specimen of Pteropurpura from the North Gape-Three Kings area, collected by Mr E. Willis of m.v. “ Ikatere ” and lodged in the collection of Mr and Mrs N. Gardner, of Auckland, as Pteropurpura cf, plorator (A. Adams and Reeve, 1850), It is a very small but excellently preserved shell

with complete variceal flanges, having a slightly taller spire and markedly larger nodules than most specimens referred to P. laetifica, but strikingly similar to P. laetifica in spiral sculpture and overall appearance. Also, the New Zealand Oceanographic Institute “North-West Slope Benthos” Cruise of October, 1968, trawled two well-preserved, dead, stained specimens of Pteropurpura very similar to P. laetifica at Station E 875, in approximately 480 m, off Ninety-Mile Beach, Northland.

As the fossil specimens of P. flemingi are badly broken, few criteria could be used to compare them with the Recent shells. The only useful measurable characters were the height of the spire (measured from inside the top of the aperture) and the diameter of the third- and fourth-to-last invervariceal spaces (measured from the base of the varix of the third-to-last space to the most inflated part of the fourth-to-last space, as shown in Text-fig. 1). Comparison of these on a graph (Text-fig. 2) showed that all fell within very narrow limits of variation except the holotype of

P. flemingi, which is significantly shorter than all others, including the paratype. The holotype of P. flemingi is considered to be an aberrant individual, and all five Mangapanian and Recent specimens are thought to be consubspecific. The variation is a little greater than that seen in older specimens of P. laetifica, but is not unexpected in view of the large range of variation of Miocene specimens. The Mangapanian to Recent specimens are consistently much smaller than the Miocene P. laetifica laetifica, and it is considered that they should be separated as the subspecies P. laetifica flemingi.

The occurrence of Pteropurpura laetifica in Recent faunas of Northland provides another example of the extension of time ranges of (apparently) Miocene species in deep-water faunas, a common feature of New Zealand outer neritic and bathyal molluscan faunas.

Dimensions are shown in Table I.

Localities: VBBB, N165/1065, cliffs east of Whangaimoana, Palliser Bay (Mangapanian, late Pliocene), holotype and one paratype, coll. P. Wellman; N.Z. Oceanogr. Inst. Station E 875, 34°39'5, 172°07'E, off Ninety-Mile Beach, Northland, in 482-485 m, two figured specimens; trawled between North Cape and Three Kings Islands, per E. Willis, m.v. “ Ikatere ”, in colln. of Mr and Mrs N. Gardner of Auckland, one live-collected young shell.

Holotype (VM23I) and paratype (VM24O) in Geology Department, Victoria University of Wellington.

Time Range: Mangapanian (see Beu, 1969, for nomenclature of New Zealand Pliocene and Lower Pleistocene stages) and Recent.

Pteropurpura laetifica waiareka n.subsp. PI. 1, Figs. 4, 6

Shell small, highly incomplete, with tall spire and long siphonal canal. Varices broadly expanded, more markedly so on the shoulder than elsewhere, aligned up the spire to form continuous flanges, three per whorl spaced regularly 120° apart, so that the shell is prominently trigonal when viewed from the apex. Whorls unusually tall for the genus, well rounded in intervariceal spaces, bearing one low, ill-defined nodule in the centre of each space, the nodules being elongate parallel to the shell axis and becoming much weaker on later whorls than they are near the apex. Spiral sculpture of about four or five low, indistinct, smooth cords on spire whorls and about eight visible on remaining portion of last whorl, all very low or absent on main shell surface but rapidly becoming more prominent at the bases of the variceal flanges, and becoming still more prominent across the flanges to form prominent fluted and spinose edges to the varices. Apertural lips thickened, other details not visible. Protoconch lost.

Dimensions: height, 40.6 mm; diameter across apertural face (left varix missing), 23.0 mm (actual), 32mm (estimated).

Type Locality: G 59481, green tuff on hillside near former Lome railway station, Waiareka Valley, near Oamaru, holotype, collected T. A. Darragh and P. A. Maxwell, Feb., 1968.

Holotype (TM4825) in New Zealand Geological Survey.

Remarks : The classical “ Lome ” locality, a green tuff bed in the Waiareka Volcanics near the site of the former Lome railway station in Waiareka Valley, about six miles north-west of Oamaru, has been collected frequently since its fauna was first described by Marwick (1926). The outcrop is among large limestone boulders near the base of a high bluff, known as Williams’ Bluff, and is now known, from oblique aerial photographs, to be a block in a large slump that has fallen from near the top of the bluff (see Frontispiece in Stradner and Edwards, 1968).

The unique specimen of the new subspecies is highly incomplete, and has only the varix to the right of the aperture in a reasonably complete condition; even this lacks large portions, and lost many small fragments during removal of the specimen from its hard green matrix. The overall appearance of the resulting specimen is close to that of Pterynotus (s.str.) elongatus (Lightfoot) {= Murex clavus Kiener), but the resemblance is very superficial. The sculpture and general form are very similar to those of Pteropurpura laetifica laetifica, and the shell differs from the nominate subspecies only in its much narrower and taller form, in its fewer, more widely spaced spiral cords, and in the much more marked increase in strength of the spiral cords over the varices.

Time Range: Kaiatan Stage (Upper Eocene).

Pteropurpura kaiparaensis (Fleming, 1962). PI. 2, Figs. 10-12 1918. Murex angasi Crosse: Suter in Marshall, Trans. N.Z. Inst. 49: 447 (not Mur ex angasi Crosse, 1863). 1918. Murex angasi Crosse: Marshall, Trans. N.Z. Inst. 50: 274 (not of Crosse). ?1944. Pteronotus cf. laetificus: Laws, Trans. R. Soc. N.Z. 73: 310. 1962. Pterynotus s.str.) kaiparaensis Fleming, Trans. R. Soc. N.Z. zool. 2(14): 110, pl. 1, fig- 1.

The species has very similar proportions to P. laetifica, but is rendered very distinct by consistently bearing three prominent, elongate nodules in each intervariceal space, causing the sculpture to have a consistently cancellate appearance

that is not seen in P. laetifica. The two specimens seen by the writer are of almost identical size, and are very small compared with adult P. laetifica laetifica. As far as can be seen from the two incomplete specimens, the varices are similar in outline to those of P. laetifica, but the details are not clear. The spiral sculpture is similar to that of P. laetifica, but there are fewer cords in P. kaiparaensis.

Pteropurpura kaiparaensis was originally recorded from Pakaurangi Point as “ Mur ex angasi Crosse ”, the species of Pterochelus that is common in south-eastern Australia. Presumably the specimen in the Marshall Collection that was made the holotype of P. kaiparaensis by Fleming is the shell that was collected by Marshall and identified by Suter. Only one other specimen has been examined by the writer. Laws (1944: 310) recorded a specimen from Pakaurangi as Pteronotus cf. laetificus Finlay, but this specimen is not lodged in any New Zealand collection at present. Laws referred to the small size of the shell, but otherwise described its features in very general terms. It is possible that Laws had a specimen of Pteropurpura laetifica, and that P. laetifica laetifica and P. kaiparaensis were sympatric at Pakaurangi Point, but it seems much more likely that Laws’ shell was a specimen of P. kaiparaensis.

Pteropurpura kaiparaensis inhabited Northland during part of the time range of P. laetifica laetifica, which occurs in younger rocks at Parengarenga Harbour, northernmost Northland. Pteropurpura kaiparaensis is regarded as a full species because of its apparently consistently much smaller size than that of the contemporaneous P. laetifica laetifica, and because the sculptural differences between the two are much larger than between any specimens of Pteropurpura laetifica laetifica.

Dimensions of Holotype: height, 28.3 mm; diameter, 14.5 mm.

Localities: Pakaurangi Point, Kaipara Harbour, Northland (Otaian?), P. Marshall Collection, New Zealand Geological Survey; N2B/861, Waiteroa Member, Pakaurangi Formation (see Jones, 1969), Coates’ Bay, Pakaurangi Point, Kaipara Harbour (late Otaian), coll. B. G. Jones, Dec., 1966, a well-preserved spire, Auckland University Geology Department.

Holotype (TM3079) in New Zealand Geological Survey; figured specimen in Auckland University Geology Department (G 5831).

Time Range: Otaian.

The holotype is stained a medium reddish brown, similar to the colour of many shells from the lower part of the section at Pakaurangi Point; shells from higher in the section are usually either fawn or unstained. Thus the holotype probably comes from low in the section and is probably Otaian in age. The species seems to be recorded only from the Otaian Stage at Pakaurangi Point.

Acknowledgments

I wish to thank Professor P. Vella, Victoria University of Wellington, Mr J. A. Grant-Mackie, University of Auckland, Mr E. W. Dawson, New Zealand Oceanographic Institute, and Mr and Mrs N. W. Gardner, of Auckland, for the loan of valuable specimens, and Mr P. A. Maxwell for the use of specimens from faunas he is monographing. Mr Maxwell and Dr C. A. Fleming, New Zealand Geological Survey, provided valuable criticism of the manuscript. The photographs reproduced in the plates are the work of Mr D. L. Homer and Mr T. R. Ullyatt, Photographic Section, New Zealand Geological Survey, and Text-fig. 2 was draughted by Mrs D. Von Sacken, New Zealand Geological Survey.

Literature Cited

BeUj A. G., 1967. Deep-water Pliocene Mollusca from Palliser Bay, New Zealand. Trans. R. Soc. N.Z. geol. 5(3) : 89-122, 2 pis.

stratigraphy. N.Z. Jl geol. Geophys. 12: 643-58, 2 figs.

Emerson, W. K., 1964. On the identity of Murex macropterus Deshayes, 1839 (Mollusca, Gastropoda). The Veliger 6(3): 151-4, pis. 19-20.

Finlay, H. J., 1930; New shells from New Zealand Tertiary beds. Part 3. Trans. N.Z. Inst. 61: 49-84, pis. 1-6.

Fleming, G. A., 1962. The genus Pterynotus Swainson (Gastropoda, Family Muricidae) in New Zealand and Norfolk Island. Trans. R. Soc. N.Z. zool. 2(14) ; 109—19, 1 pi.

Jones, B. G., 1969. The stratigraphy and structure of Pakaurangi Point, Kaipara, New Zealand. Trans. R. Soc. N.Z. geol. 6(17): 219-46, 10 figs., 4 pis.

Keen, A. M., 1964. Purpura , Ocenebra and Muricanthus (Gastropoda) : request for clarification of status. Bull. zool. Nom. 21: 235-9.

Laws, C. R., 1944. The molluscan faunule at Pakaurangi Point, Kaipara—No. 3. Trans. R. Soc. N.Z. 73: 297-312, pis. 43-5.

Marwick, J., 1926. Molluscan fauna of the Waiarekan Stage of the Oamaru Series. Trans. N.Z. Inst. 56; 307-16, pi. 72, 1 fig.

13: 177 pp., 18 pis.

Ponder, W. F., 1968. Nomenclatural notes on some New Zealand rachiglossan gastropods with descriptions of five new species. Rec. Dom. Mus. Wellington 6(4) : 29—47, 62 figs.

Powell, A. W. 8., 1967. New Zealand molluscan systematics with descriptions of new species; Part 6. Rec. Auckland Inst. Mus. 6(3) : 185—96, pis. 36, 37.

Stradner, H.; Edwards, A. R., 1968. Electron microscope studies on Upper Eocene coccoliths from the Oamaru Diatomite, New Zealand. Jahrb. geol. Bundesanst. 13: 1-66, 10 figs., 48 pis.

Tate, R., 1888. The gastropods of the older Tertiary of Australia, Part 1. Trans. R. Soc. S. Aust. 10: 91-176, 13 pis.

Yokes, E. H., 1964. Supraspecific groups in the subfamilies Muricinae and Tritonaliinae (Gastropoda; Muricidae). Malacologia 2(1): 1-41, 3 pis.

Wood, B. L., 1969. Geology of Tuatapere Subdivision, western Southland (Sheets 5167, 5175). Bull. N.Z. geol. Surv. n.s. 79: 161 pp., 53 figs., 2 maps.

Dr A. G. Beit, N.Z. Geological Survey, P.O. Box 30368, Lower Hutt.

* Footnote added in proof: In Opinion 886 (published in Bull. zool. Nomencl. 26(3/4) : 128, October 24, 1969), the International Commission on Zoological Nomenclature suppressed the generic name Tritonalia Fleming, 1828.

height diameter height of spire (h) diameter of 3rd and 4 th intervariceal spaces (d) h / d * ' d Holotype 20.0 12.8 11.3 10.0 1.13 Paratype 19.3 1.2 11.2 9.0 1.24 N.Z .0.1, sta. E.875, larger 35-0 19.9 14.7 10.7 1 .37 N.Z .0.1. sta. E.875, smaller 34.0 19.7 18.0 11.9 1 .51 N.W. Gardner colln. 21 .4 13.2 8.6 6.3 1.36

Table I.—Dimensions (in mm) of Pteropurpura laetifica flemingi (Beu).