Leucosyrinx sansibarica, Thiele, 1925

Kantor, Yuri I., Fedosov, Alexander & Puillandre, Nicolas, 2025, Revision of the Indo-Pacific species of the genus Leucosyrinx Dall, 1889 (Neogastropoda: Conoidea: Pseudomelatomidae), European Journal of Taxonomy 999, pp. 1-126 : 105

“ Leucosyrinx ” sansibarica Thiele, 1925

Fig. 34D–F

Leucosyrinx sansibarica Thiele, 1925: 181 (215), pl. 24 (36) fig. 1.

Brachytoma griffithii (not Gray, 1833) – von Martens 1904: 84. — Thiele 1904: 173, pl. 9 fig. 73.

Leucosyrinx sansibarica – Powell 1969: 340 (23-404), pl. 258 fig. 5.

Type material

Syntypes

EAST AFRICA • 2 specs; Pembakanal; 5°24′ S, 39°19′ E; depth 818 m; Valdivia, stn 246 (2 dead); ZMB ?.

GULF OF ADEN • 2 specs; 13°2′ N, 46°41′ E; depth 1469 m; Valdivia, stn 271; ZMB Mol 60089 , ZMB Mol 109387 .

Remarks

The species was established for Brachytoma griffithii sensu von Martens (1904) , not Gray, 1833. Von Martens (1904) cited material from two Valdivia stations: station 246 (Pemba Channel, off Zanzibar) and station 271 in the Gulf of Aden. Two dead specimens were collected at the first station, while several live specimens were collected at station 271. Thiele (1904: 173, pl. 9 fig. 73) illustrated the radula of the species without indicating the exact specimen, describing a radula typical of Comispira with a large central formation. Von Martens (1904) proposed a variety, gracilior, for specimens from off Zanzibar. When Thiele (1925) renamed the species Leucosyrinx sansibarica , he did not designate a holotype or a type series, nor did he provide a formal description, but from the specific epithet, it can be inferred he referred to the specimens from station 246. His illustration aligns with var. gracilior as described by von Martens, 1904 (“Martens distinguished a var. gracilior , which I have illustrated in Figure 1 .”—my translation).

We were unable to examine the specimens from the station 246, but the specimens from the station 271 in the Gulf of Aden are not conspecific. While one specimen represents the typical Leucosyrinx (ZMB Mol 60089, Fig. 34E ), the other, with a row of subsutural knobs, belongs to Comispira (ZMB Mol 109387, Fig. 34F ), rather similar to C. obtusigemmata (see below). The specimen illustrated by Thiele (1925) ( Fig. 34D ) is generally similar to the specimen of Leucosyrinx from the Gulf of Aden ( Fig. 34E ), differing mainly in its slenderer shell (a variable intraspecific character in Leucosyrinx ) and a much shallower anal sinus. It should be noted that in several of Thiele’s (1925) line drawings, the illustrated anal sinus does not match the actual sinus in the same specimen. We therefore consider L. sansibarica as belonging to the genus, although a final decision requires examining the illustrated specimen (currently unavailable) and designating a lectotype.

Distribution

Tanzania to Gulf of Aden, 818–1469 m.

Figures

Fig. 34. A–F. Doubtful species of Leucosyrinx Dall, 1889. A. “Leucosyrinx” caecilia Thiele, 1925, holotype, ZMB Mol 109385, SL 7.5 mm (photo courtesy of Museum für Naturkunde). B. “Leucosyrinx” canyonensis (Dell, 1956), holotype, MNZ, M.009262, SL 9.3 mm (photo from the website of MNZ, https://collections.tepapa.govt.nz/object/151638). C. “Leucosyrinx” erna Thiele, 1925, syntype, ZMB Mol 109384, SL 7.8 mm (photo courtesy of Museum für Naturkunde). D–F. “Leucosyrinx” sansibarica Thiele, 1925. D. Original drawing (Thiele 1925: pl. 24 (36) fig. 1),? ZMB, SL 45 mm. E. Syntype, ZMB Mol 60089, Gulf of Aden, SL 42.6 mm (photo courtesy of Museum für Naturkunde). F. Syntype, ZMB Mol 109387, Gulf of Aden, SL 34.5 mm (= Comispira) (photo courtesy of Museum für Naturkunde). G–H. Types of species excluded from Leucosyrinx and Comitas H.J. Finlay, 1926. G. Rhodopetoma amycus (Dall, 1919) comb. nov., holotype, USNM 226163, SL 21.5 mm (photo courtesy of USNM). H. Burchia clionella (Dall, 1908), syntype, USNM 123125, SL 35.2 mm (photo courtesy of USNM).

Fig. 1. Bayesian phylogenetic tree obtained with the cox1 dataset. Posterior probabilities (> 0.80) are shown for each node. The SSH containing several specimens are collapsed for saving space, the number in brackets indicates the number of specimens in the corresponding collapsed clade.