Cryptogemma periscelida, (DALL, 1889)

Zaharias, Paul, Kantor, Yuri I., Fedosov, Alexander E., Criscione, Francesco, Hallan, Anders, Kano, Yasunori, Bardin, Jérémie & Puillandre, Nicolas, 2020, Just the once will not hurt: DNA suggests species lumping over two oceans in deep-sea snails (Cryptogemma), Zoological Journal of the Linnean Society 190, pp. 532-557 : 549

CRYPTOGEMMA PERISCELIDA (DALL, 1889)

( FIG. 10I–K)

Pleurotoma periscelida Dall, 1889 . 283 m (USS Albatross expedition, st. 2143, collected on 23 March 1884) and 196 m, off Hatteras , North Carolina.

Remarks: The protoconch is unknown, because it is consistently eroded in all examined material, even in younger specimens.

The radula is of medium length (part of youngest section lost),> 1.9 mm (> 0.22 of AL), composed of> 50 transverse rows of teeth. The marginal teeth are 107– 116 µm long (mean 110 µm, N = 5 or 1.25% of AL), duplex. The anterior (inner) 0.4 of the tooth length is solid, narrow lanceolate in dorsal view. In the posterior part, the major and accessory limbs are medium broadly bifurcating, and the accessory limb has a clear constriction and is bent at less than half tooth length, thin, nearly the same length and width as major limb. The central formation has a long, narrow, sharp carinated cusp and lateral flaps with distinct posterior and posterolateral margins. The flaps are completely fused with the cusp ( Fig. 7D).

This species has been described from the Gulf of Mexico , although specimens from Suriname and from the MNHN recent expedition GUYANE 2014 (French Guiana) were also collected. This is the only ‘ Gemmula’ - like species to be found exclusively in the Atlantic Ocean, where it occurs in a depth range of 200–800 m.

List of COI diagnostic sites (position: character state): [352: C, 412: G, 655: C].

Distribution: Found in the Gulf of Mexico, north to the Carolina coast and south to French Guiana ( Fig. 4B), from a depth of ~200 to ~ 500 m ( Fig. 5).