The Type Specimens of Belemnopsis tanganensis (Futterer) 1894 (Cephalopoda, Dibranchiata)

Transactions of the Royal Society of New Zealand : Geology, Volume 2, Issue 8, 20 November 1963, Page 131

The Type Specimens of Belemnopsis tanganensis (Futterer) 1894 (Cephalopoda, Dibranchiata)

G. R. Stevens

By

New Zealand Geological Survey, Lower Hutt

[Received by the Editor, May 28, 1963.]

Abstract

The original specimens of the Tanganyikan belemnite, Belemnopsis tanganensis (Futterer) are re-figured and re-described. Previous records of the species are examined; it seems to be characteristic of the Upper Oxfordian-Middle Kimeridgian of East Africa and Southern Arabia. Records of the species from Madagascar, India, Indonesia and N.W. Australia appear to be based on misidentifications.

Belemnopsis tanganensis was originally described from Tanganyika (Futterer, 1894) and has been identified by later workers in collections from Madagascar, Kenya, Somaliland, Ethiopia, Aden, India (N.W. Punjab and Kachh), Indonesia and N.W. Australia. Futterer’s original specimens were kindly loaned to the writer by Prof. Dr W. O. Dietrich and Prof. Dr W. Gross, of the Geologisch-palaonto-logisches Institut, Humboldt Universitat, East Berlin, and study of these showed the inadequacy of the line engravings on which the species was originally based. Study of the specimens also cast doubt on many of the later identifications of B. tanganensis. Therefore Futterer’s original specimens are re-figured (PI. 1) and a complete synonymy, diagnosis and description of tanganensis, based on their study, is presented below.

SYNONYMY

1894. Belemnites tanganensis Futterer: 30-2, PI. 5, figs. 2, 3. 1910. cf. Belemnites tanganensis Futterer; Dacque: 26-7, PI. 2, figs. 5, 6.

1910. cf. Belemnites tanganensis Futterer; Tipper: 337, PI. 35, figs. 2, 3. 1914. Belemnites cf. alfuricus Boehm; Zwierzycki: 18, PI. 1, fig. 1.

1925. Belemnites ( Belemnopsis ) tanganensis Futterer; Stefanini: 153—4, PI. 27, figs. 7, 8.

1925. Belemnites ( Belemnopsis) tanganensis Futterer; Weir: 94-5. 1930. Belemnites ( Belemnopsis) tanganensis Futterer; Basse: 122, 133.

1933. Belemnopsis cf. tanganensis (Futterer) (partim); Dietrich: 22—3, PI. 1, figs. 10-12 (non figs. 10 and 12).

1933. Belemnites (Belemnopsis ) tanganensis Futterer {partim); Stefanini: 47—50, PL 4, figs. 2, 6-17 (non figs. 3-5).

1935. Belemnopsis tanganensis (Futterer); Spath: 218, PI. 25, fig. 2.

1956. Belemnopsis tanganensis (Futterer); Arkell; 309, 322-3. non 1906 Belemnites tanganensis Futterer; Lemoine: 145, 147.

non 1907 Belemnites alfuricus Boehm: 56-7, PI. 8, figs. 4,5, 7—ll. non 1911 Belemnites tanganensis Futterer; Lemoine: 9.

non 1927—33 Belemnopsis tanganensis (Futterer); Belemnopsis aff. tanganensis (Futterer); Spath: 9-10, 660-1, PI. 1, figs. 3,4; PI. 124, figs. 3, 8. non 1929 Belemnopsis tanganensis (Futterer); Stolley: 177-9, PI. 5, figs. 13-20.

non 1929 Belemnopsis sp., aff. tanganensis (Futterer); Stolley: 179-80, PL 5, fig. 12. non 1929 Belemnites ( Belemnopsis) tanganensis Futterer; Weir: 18, PI. 2, fig. 23; PI. 5, figs. 19-20. non 1930 Belemnopsis tanganensis (Futterer); Weir: 90, PI. 10, fig. 3. non 1930 Belemnites tanganensis Futterer; Besairie: 194, PI. 11, fig. 12.

(? non) 1934 Belemnopsis tanganensis (Futterer); Spath: 21—2. non 1935 Belemnopsis cf. tanganensis (Futterer); Stolley: 53-4, PL 2, fig. 5. non 1951 Belemnopsis cf. tanganensis (Futterer); Belemnopsis sp., aff.

tanganensis (Futterer); Brunnschweiler: 6-8. non 1956 Belemnopsis tanganensis (Futterer); Besairie and Collignon: 54. non 1958 Belemnopsis cf. B. tanganensis; McWhae et al.: 90.

Diagnosis

Guard elongate, moderately hastate. Apical and stem cross-sections depressed, alveolar cross-sections compressed. Median ventral groove very characteristic: shallow, but broad in relation to the width of the guard. The groove maintains its character throughout almost the length of the guard and shallows only some 3-4 mm from the apex.

Legtotype

Two syntypes are available, the originals of Futterer (1894) PI. 5, figs. 2,2 a —c, 3,3 a-c. Both are preserved in the collections of the Geologisch-palaontologisches Institut, Humboldt Universitat, East Berlin, and were collected by Lieder in 1893 from Tanga, Tanganyika. The original specimen of Futterer’s PI, 5, figs. 2,2 a-c is designated as the Lectotype of Belemnopsis tanganensis (Futterer). The Lectotype is figured as PI. 1, figs. 1-3 in the present work and the remaining syntype (the original of Futterer’s PI. 5, figs. 3,3 a-c) as PI. 1, figs. 4-6.

Description

Guard elongate and moderately hastate. Length 7-8 times maximum transverse diameter.

Outline symmetrical and moderately hastate. Apical angle 19°. The sides of the guard diverge gradually from the apex. The position of maximum transverse inflation is usually in the anterior half of the guard. Anteriorly to this the sides of the guard gradually converge, the width of the guard reaching a minimum

at the approximate position of the protoconch. Anterior to the protoconch the sides diverge slightly to accommodate the phragmocone.

Profile slightly asymmetric, the ventral surface of the guard being more inflated than the dorsal surface. This inflation has directed the apex dorsally. The profile is less hastate than the outline. The dorsal and ventral surfaces diverge gradually from the apex and then converge slightly in the vicinity of the protoconch. Anterior to the protoconch, the dorsal and ventral surfaces diverge to accommodate the phragmocone.

Cross-sections of the apical and stem regions are depressed, but the cross' sections of the alveolar region are compressed.

Median ventral groove shallow (o.7mm deep, where sagittal diameter is B.6mm), but broad in relation to the width of the guard (2.5 mm wide, where transverse diameter is 9.5 mm). The groove maintains its character throughout almost the entire length of the guard, and shallows only some 3-4 mm from the

apex. Anteriorly, the groove does not gradually deepen, as in many other species of Belemnopsis, but narrows in the anterior portion of the alveolar region, where the phragmocone approaches the surface of the guard. Dorsal grooves are absent, and lateral lines have not been observed in the available specimens.

Apical line excentric and ventrally placed. Alveolar angle about 22°.

Age and Stratigraphic Horizon

On the basis of this present revision B. tanganensis is known to occur in Tanganyika, Kenya, Somaliland, Ethiopia and Aden. Its presence in Madagascar, India, Indonesia and N.W. Australia is not proven (see Stevens in press for further discussion).

The precise age of Futterer’s specimens is unknown, but two Oxfordian ammonite faunas are known from the neighbourhood of Tanga (Arkell, 1956: 328). In Somaliland B. tanganensis is known from the Gahodleh Shales, Wanderer Limestone and Daghani Shales (Arkell, 1956: 309; Spath, 1935: 207-8) correlated by Arkell with the ? Upper Oxfordian and Middle Kimeridgian. Arkell (1956: 322-3) also records B. tanganensis from the Upper Oxfordian and Lower Kimeridgian of Kenya. The Lower Kimeridgian material has not been seen by the writer, but identification of B. tanganensis is confirmed for Upper Oxfordian material from Port Rietz, Mombasa (Sedgwick Museum collections). Ammonites associated with Tipper’s specimens of B. tanganensis from Aden have been dated by Arkell (1956: 301) as Lower and Middle Kimeridgian.

Thus B. tanganensis appears to range from Upper Oxfordian to Middle Kimeridgian. Its restriction to East Africa and Southern Arabia may perhaps be taken as indicating distribution along Arkell’s Trans-Erythraean Trough, branching off the southern margin of the Tethyan seaway in the Jurassic (Textfig. 1).

Acknowledgments

This paper is part of a study carried out at the Sedgwick Museum, University of Cambridge, during the tenure of a Shell Post-Graduate Scholarship in Science. This financial assistance is gratefully acknowledged.

The writer wishes to thank Mr A. G. Brighton for encouragement and advice in all aspects of the work, and Professor O. M. B. Bulman, F.R.S., through whose hospitality he enjoyed the facilities of the Sedgwick Museum. The paper was kindly read in draft form by Dr G. A, Fleming, New Zealand Geological Survey, D.S.I.R.

Prof. Dr W. O. Dietrich and Prof. Dr W. Gross, of the Geologisch-palaonto-logisches Institut, Humboldt Universitat, East Berlin, are sincerely thanked for arranging for the loan to the writer of Futterer’s original specimens.

References

Arkell, W. J., 1956. Jurassic Geology of the World. Edinburgh & London: Oliver & Boyd.

Bramkamp, R. A., Steineke, M., 1952. Jurassic Ammonites from Jebel Tuwaiz, Central Arabia. Phil. Trans. 2368: 241-313.

Basse, E., 1930. Contribution a I’Etude du Jurassique Superieur (Facies Corallien) en Ethiopie et en Arabic Meridionale. Mem. Soc. geol. Fr. T. 6 (n.s. ) No. 14: 122-23, 133.

Besairie, H., 1930. R echerches Geologiques a Madagascar. Toulouse; Henri Basuyau.

Collignon, M., 1956. Madagascar. Lexique Strat. Internal. 4 (11).

Boehm, G., 1907. Beitrage zur Geologic von Niederlandisch-Indien. 1: Die Siidkiisten der Sula-Inseln Taliabu und Mangoli. Pt. 2: Der Fundpunkt am Oberen Lagoi auf Taliabu. Palaeontographica Suppl. 4, Abt. 1, Abs. 2.

Brunnschweiler, R. 0., 1951. Notes on the Geology of Dampier Land, N.W. Australia. Aust. J. Sci. 14: 6-8.

Dacque, E., 1910. Dogger und Malm aus Ostafrika. Beitr. Paldont. Geol. Ost.-Ung. 23: 1-63.

Dietrich, W. 0., 1933. Zur Stratigraphic und Palaeontologie der Tendaguruschichten. Palaeontographica Suppl. 7, Rh. 2, Teil 2, Lief. 1.

Futterer, K., 1894. Beitrage zur kenntniss des Jura in Ost-Afrika. Z. dtsch. geol. Ges. 46: 1-49.

Lemoine, P., 1906. Etudes geologiques dans le Nord de Madagascar. Paris: Hermann.

McWhae, J. R. H., Playford, P. E., Lindner, A. W., Glenister, B. F., Balme, B. E., 1948. The Stratigraphy of Western Australia. /. geol. Soc. Aust. 4 (2).

Spath, L. F., 1927-33. Revision of the Jurassic Cephalopod Fauna of Kachh (Gutch). Palaeont. indica n.s. Vol. 9, Mem. 2.

1934. The Jurassic and Cretaceous Ammonites and Belemnites of the Attock District. Palaeont. indica n.s. Vol. 20, Pt. 4.

1935. The Mesozoic Palaeontology of British Somaliland. 10. The Cephalopoda. Hargeisa: Govt, of the Somaliland Protectorate.

Stefanini, G., 1925. Description of Fossils from South Arabia and British Somaliland. Appendix 1 in; Little, O. H. The Geography and Geology of Makalla (South Arabia ), pp. 143-250. Cairo; Govt. Press.

1933. Molluschi del Giuralas della Somalia. Paleontogr. ital. 32, Suppl. 1; 1-53.

Stevens, G. R., in press. The Jurassic and Cretaceous Belemnites of New Zealand and a Review of the Jurassic and Cretaceous Belemnites of the Indo-Pacific Region. N.Z. geol. Surv. Palaeont. Bull. 36.

Stolley, E., 1929. Hber Ostindische Jura-Belemniten. Paldont. v. Timor Lief 16, Abh. 29.

Teil. Neues Jb. Min. Geol. Paldont. 73 (B-B) Abt. B: 42-69.

Tipper, G. H., 1910. Notes on Jurassic Fossils Collected by Captain R. E. Lloyd near Aden. Rec. geol. Surv. India, 38; 336-41.

Weir, J., 1925. Rocks and Fossils from Somaliland; Part 6, Brachiopoda, Lamellibranchiata, Gastropoda and Belemnites. Monogr. geol. Dept. Hunter. Mus. 1: 79-110.

1929. Jurassic Fossils from Jubaland, East Africa. Monogr. geol. Dept. Hunter. Mus. 3.

— 1930. Reports on Geological Collections from the Coastlands of Kenya Colony. 4: Mesozoic Brachiopoda and Mollusca from Mombasa. Monogr. geol. Dept. Hunter. Mus. 4: 77-102.

Zwierzycki, J., 1914. Wissenschaftliche ergebnisse der Tendaguru Expedition 1909-1912; Die Cephalopodenfauna der Tendaguru-schichten in Deutsch-Ostafrika. Arch. Biontol., Berl. 3 (4): 7-96.

Dr G. R. Stevens, N.Z. Geological Survey, P.O. Box 368, Lower Hutt.

A B mm mm (i) length (distance from apex to protoconch) 65 64 (ii) distance from apex to position of maximum transverse diameter 39 36 (iii) maximum transverse diameter 10.0 7.7 (iv) minimum transverse diameter 8.5 6.5 (v) maximum sagittal diameter 8.5 6.5 (vi) minimum sagittal diameter 9.0 6.0 (vii) distance between positions of maximum and minimum transverse diameter .. 26 28

Dimensions of the Lectotype (Column A) and Syntype (Column B) are as follows: