Pseudotrophonopsis Merle, 2024

Merle, Didier, Pacaud, Jean-Michel, Ledon, Daniel & Goret, Bernard, 2024, New Cenozoic Muricidae (Mollusca: Gastropoda) from Europe, Geodiversitas 46 (15), pp. 495-551 : 535

Genus Pseudotrophonopsis Merle , n. gen.

( Fig. 22 I-L)

urn:lsid:zoobank.org:act:A8FA7CDF-EBB1-4B5C-988E-14A31F6D1689

TYPE SPECIES. — Buccinum defossum Pilkington, 1804 , middle Eocene (Bartonian) of England (Hampshire) ( Fig. 22 I-K), and late Eocene (Priabonian) of France (Paris Basin) ( Fig. 22L ).

ETYMOLOGY. — Name based on the Greek prefix pseudo (false), because the superficial resemblance of the type species with members of the genus Trophonopsis Bucquoy & Dautzenberg, 1882 .

INCLUDED SPECIES. — Buccinum defossum Pilkington, 1804 [synomym: Fusus sublamellosus Deshayes, 1835 ], England, Hampshire Basin, middle Eocene (Bartonian) and France, Paris Basin, late Eocene (Priabonian).

DIAGNOSIS. — Smooth multispiral protoconch ( Fig. 22K ). Biconic teleoconch with rounded whorls. P6 not atrophied. IP, ADP, MP, ADP present. Primary P1 to P6 present on first whorl ( Fig. 22K ). Coarse secondary cords equal in strength to primary cords. Varices low, formed by one short abaxial lamella. No P1 spine. No shoulder sinus. Posterior sinus shallow. Columellar lip smooth. Internal denticles D1 to D6 split. ID missing.

COMMENTS

This strange species differs from members of Jsowerbya Merle, 2005b and Beyregrex Merle , n. gen. by having rounded whorls, no shoulder sinus and by having strongly developed secondary cords. Because of its rounded whorls, it resembles members of Nucellopsis , but they are distinguishing by their buccinoid shape and by a later appearance of the primary cords. The phylogenetic analysis (Winclada tree, Fig. 1 ) suggests that it could represent a stem group of Jsowerbya . We therefore propose the new genus Pseudotrophonopsis Merle , n. gen. as P. defossa ( Pilkington, 1804) , n. comb. cannot be attributed to Jsowerbya or Beyregrex Merle , n. gen. Pseudotrophonopsis defossa n. comb. occurs in the Bartonian from Hampshire ( England) and is known in the Priabonian from the Paris Basin, where it was identified as Fusus sublamellosus Deshayes, 1835 . The protoconch of the English and French populations ( Fig. 22K ) is similar and the teleoconch of the French population is only less thick (personal observation DM). Therefore,we believe that they belong to the same species. Glibert (1963) recorded this species in the Bartonian from the Paris Basin, but we cannot confirm this record based on material in the examined collections (MNHN and private collections). It is possible that this species was mistaken for Jsowerbya depauperata ( Deshayes, 1865) .

Figures

FIG. 22. — Species of the informal group Jsowerbyia-Beyregrex n. gen.-Pseudotrophonopsis n. gen.: A, B, Jsowerbya sexdentata (Sowerby, 1823), BMNH GG22673 (Burton coll.), Colwell Bay, Wight Island, England, late Eocene (Priabonian); C, D, Beyregrex sarroniensis (Carez, 1870), n. comb., MNHN.F.J02576 (figured specimen of Cossmann & Pissarro 1911: pl. 35, fig.169-14), Sarron, Oise, Paris Basin, France, early Eocene (Ypresian); E, F, B. hantoniensis (Edwards, 1866),n. comb.,Morton coll., Middle Headon Brockenhurst bed, Whitecliff Bay, Wight Island, England,late Eocene (Priabonian); G, H, B. pereger (Beyrich, 1854), n. comb.,MNHN.F.A90561 (Lozouet & Maestrati coll.), Auvers-Saint-Georges,Essonne,Paris Basin,France, early Oligocene (Rupelian); I-L, Pseudotrophonopsis defossa (Pilkington, 1804), n. comb.: I, J, MNHN.F.J17634 (Cossmann coll.), Barton-on-Sea, Hampshire, England, middle Eocene (Bartonian); K, A. Smith coll. (juvenile specimen), upper Barton bed H, Barton Highcliffe; L, MNHN.F.A90560 (Munier-Chalmas coll.), Le Vouast, Oise, late Eocene (Priabonian). Scale bars: A-J, L, 5 mm; K, 1 mm. Credits: A, B, D. Serrette (MNHN); C, D, G-J, L, P. Loubry (MNHN/CNRS); E-F, K, A. Morton.

FIG. 1. — Strict Consensus tree of 7 equally parsimonious trees (length 107, ci 0.53, ri 0.78) generated by Winclada and computed using the option Heuristic Analysis (mult* max*), all characters non additive.