Conus (Taranteconus) samadiae, Tenorio & Puillandre, 2023

Tenorio, Manuel J. & Puillandre, Nicolas, 2023, Revision of the deep-water cone snail fauna from New Caledonia (Gastropoda, Conoidea), European Journal of Taxonomy 896, pp. 1-134 : 114-116

Conus (Taranteconus) samadiae sp. nov.

urn:lsid:zoobank.org:act:A81F054F-DB47-47CB-9E2C-53197AB6C74F

Figs 2 , 85A–G, L , 86

Etymology

The species is dedicated to Sarah Samadi, professor at the MNHN. Sarah Samadi has been the cruise leader of many expeditions of the TDSB program, including in New Caledonia. She also initiated the DNA barcoding programme of the marine benthic fauna at the MNHN, that led to the discovery of many new taxa.

Material examined

3 lots (3 specimens). See Supp. file 1.

Type material

Holotype NEW CALEDONIA • lv, 16.5 mm; Plateau des Chesterfield , off New Caledonia, stn DW5035; 19°50′ S, 158°30′ E; 230‒260 m depth; 22 Sep. 2017; KANADEEP expedition; MNHN-IM-2013-48261 ( Fig. 85A–B, L ).

Paratypes NEW CALEDONIA • 1 dd, 16.7 mm; between Plateau des Chesterfield and Bellona Plateau, off New Caledonia , stn DW5026; 20°22′ S, 158°40′ E; 360‒410 m depth; 21 Sep. 2017; KANADEEP expedition; MNHN-IM-2018-12309 ( Fig. 85C–D ) • 1 dd, 12.8 mm; off New Caledonia , stn DW3903; 19°52′ S, 165°50′ E; 580 m depth; 22 Sep. 2011; EXBODI expedition; MNHN-IM-2014-7986 ( Fig. 85E–G ) .

Description

MORPHOMETRIC PARAMETERS. S L = 12–17 mm (mean S L = 15.3 mm); RD = 0.52–0.57; RSH = 0.28–0.29; PMD = 0.79–0.85.

SHELL. Small to very small. Maximum length: 16.7 mm. Shell profile elongated conical to conoid-cylindrical, with straight sides adapically, very slightly concave below. Spire high, of straight to slightly sigmoid outline, giving a biconic appearance to the overall shell profile. Protoconch white, paucispiral of 1.5 whorls ( Fig. 85G ). 2–3 early teleoconch whorls nodulose, flat or slightly concave. Early teleoconch whorls with 4 strong cords crossing the nodules. Teleoconch whorls with 4–5 flat cords forming 4–5 spiral grooves becaming rather obsolete on the last whorl. Shoulder angulate or subangulate, with ocasional presence of a ridge. Basal third with rather indistinct spiral grooves. Early teleoconch whorls white. Late teleoconch whorls brown with axial white streaks. Last whorl brown with large axial white areas overlaid in variable amount with spiral rows of alternating brown and white dots and dashes from base to shoulder. The white dots and dashes eventually fuse together, forming chevron markings. Aperture narrow, purplish white.

ANIMAL. The animal or operculum has not been observed.

RADULAR TOOTH. Radula from the holotype studied ( Fig. 85L ). Radular tooth of medium relative size (S L / T L = 52), with a short apical barb. Anterior section shorter than the posterior section of the tooth (T L /AP L = 2.78). Waist well marked. Blade pointed, covering slightly more than one half of the anterior section (100 B L /AP L = 59 %). Short serration with 4–5 denticles, arranged in one row ending in a prominent, pointed terminating cusp. A basal spur is present.

Distribution and habitat

Specimens have been found in two separate areas: Coral Sea (Plateau des Chesterfield and N Bellona Plateau) at depths of 200–400 m, and Loyalty Ridge (Récifs de l’Astrolabe-Sud) in a depth of 580 m. Most likely endemic to New Caledonia.

Remarks

In the phylogeny ( Fig. 2 ) the analysed specimen of C. (T.) samadiae sp. nov is sister to C. (T.) chiangi and C. (T.) polongimarumai , hence its placement in the subgenus Taranteconus at this stage. The radular tooth of C. (T.) samadiae ( Fig. 85L ) exhibits features which are also present in the radular teeth of C. (T.) chiangi ( Fig. 82M ) and C. (T.) polongimarumai ( Fig. 82N ). The shell of C. (T.) samadiae is morphologically most similar to that of Profundiconus stahlschmidti Tucker & Tenorio, 2014 ( Fig. 85H ) and of Profundiconus pacificus (Moolenbeek & R̂ckel, 1996) ( Fig. 85I ) in shape and pattern. None of these two species has been examined using DNA, and the morphology of their radular teeth is unknown. These taxa had only been tentatively placed in the genus Profundiconus . However, given the similarities in shell shape and pattern of these species to those of C. (T.) samadiae , as shown in Fig. 85 , it seems reasonable to assume that both pacificus and stahlschmidti are not members of the genus Profundiconus but instead are typical Conus , and likely of the same subgenus as C. (T.) samadiae . We therefore assign pacificus and stahlschmidti to Conus (Taranteconus) . It is possible that other alleged species of Profundiconus such as P. lani or P. dondani might change their taxonomic placement if their radular teeth and/or DNA are examined. The shell of C. (T.) samadiae is smaller than that of C. (T.) pacificus . It has an elongate conical rather than cylindrical-fusiform profile (RD 0.52–0.57 for samadiae versus 0.48–0.52 for pacificus ), with a spire similar in height but straight or slightly sigmoid in profile, rather than slightly convex as in C. (T.) pacificus . The spire whorls of C. (T.) samadiae bear 4–5 spiral grooves, whereas C. (T.) pacificus has two on the early whorls, and only one on the last whorl. The species C. (T.) stahlschmidti , known from the Togian Islands in Sulawesi, Indonesia, is on average smaller. Its shell profile is similar to that of C. (T.) samadiae , but differs mainly by the sculpture of the early teleoconch whorls: in C. (T.) samadiae the 2–3 early teleoconch whorls are nodulose, whereas nodules are present only in the first early teleoconch whorl of C. (T.) stahlschmidti . The nodules in stahlschmidti have longitudinal bars on the whorl tops reaching the suture with the protoconch whorls, but these structures seem to be absent in both C. (T.) samadiae and C. (T.) pacificus . The elusive species Profundiconus scopulicola Okutani, 1972 ( Fig. 85J ) from Japan bears some resemblance to C. (T.) samadiae , but its shell is more rounded at the shoulder, has a more pyriform last whorl profile, and a different shell pattern. The shell of the species Conus (Mitraconus) cylindraceus Broderip & G.B. Sowerby I, 1830 ( Fig. 85K ) may exhibit a similar shape, but it attains a larger adult size, and it has a multispiral protoconch, apart from evident differences in shell pattern. This species is also distinct using DNA (cox1) from C. (T.) samadiae ( Fig. 2 ).

Figures

Fig. 2. Cox1-based Bayesian phylogeny. Posterior probabilities (> 0.95) and bootstrap values (> 90) from the ML analysis are provided for each node. Intraspecific relationships are collapsed. Subgenus names are indicated on the right.

Fig. 85. A–G. Conus (Taranteconus) samadiae sp. nov. A. Holotype, Plateau des Chesterfield, Coral Sea, 230‒260 m depth, 16.5 mm (MNHN-IM-2013-48261). B. Ventral view of specimen in specimen A. C. Paratype, between Plateau des Chesterfield and Bellona Plateau, Coral Sea, 360‒410 m depth, 16.7 mm (MNHN-IM-2018-12309). D. Ventral view of specimen in C. E. Paratype, Loyalty Ridge, off New Caledonia, 580 m depth, 12.8 mm (MNHN-IM-2014-7986). F. Ventral view of specimen in E. G. Protoconch of paratype MNHN-IM-2014-7986. – H. Profundiconus stahlschmidti Tucker & Tenorio, 2014. Holotype, Pasir Tengah Atoll, Togian Islands, Sulawesi, Indonesia,10‒12 m depth, 10.5 mm (SMF 336434). – I. Conus pacificus Moolenbeek & R̂ckel, 1996. Holotype, Banc Bayonnaise, off Wallis & Futuna Islands, 597‒600 m depth, 20.2 mm (MNHN-IM-2000-2531). – J. Profundiconus scopulicola Okutani, 1972. Holotype, Hyotanse Bank, Izu-Shichito Island, off Honshu, Japan, 200 m depth, 22 mm (NSMT Mo 64688). – K. Conus (Mitraconus) cylindraceus Broderip & Sowerby, 1830. Récif Pétrie, off New Caledonia, 360‒410 m depth, 9.5 mm (MNHN-IM-2018-12484). – L. Conus (Taranteconus) samadiae sp. nov. Radular tooth of the holotype. Scale bars = 10 mm, unless otherwise stated.

Fig. 86. Bathymetric range and distribution map for Conus (Taranteconus) samadiae sp. nov. Red circles indicate the points where the species was collected.

Fig. 82. A–H. Conus (Taranteconus) chiangi (Azuma, 1972). A. Banc Kaimon Maru, Norfolk Ridge, 231–233 m depth, 16.7 mm. B. Banc P, Norfolk Ridge, 185–207 m depth, 14.9 mm. C. Banc Munida, Norfolk Ridge, 180–220 m depth, 16.1 mm. D. Banc Crypthélia, Norfolk Ridge, 187‒197 m depth, 17.1 mm. E. Norfolk Ridge, 262‒290 m depth, 15 mm. F. Same collection data as for specimen E, 18 mm. G. S New Caledonia, 200 m depth, 14 mm. H. Protoconch of specimen A. – I–L. Conus (Taranteconus) polongimarumai (Kosuge, 1980). I. Banc Munida, Norfolk Ridge, 180‒220 m depth, 20.5 mm. J. Grand Passage, 277‒289 m depth, 19.4 mm. K. Same collection data as for specimen J, 18.9 mm. L. Same collection data as for specimen J, 17.3 mm. – M. C. (T.) chiangi. Radular tooth, specimen from Bohol Island, Philippines, 19.8 mm (MNCN). – N. C. (T.) polongimarumai. Radular tooth, specimen from Pouembout, New Caledonia, 21 mm (Frank Leterrier coll.). Scale bars = 10 mm, unless otherwise stated.