Cryptogemma aethiopica, (THIELE, 1925)

CRYPTOGEMMA AETHIOPICA (THIELE, 1925) View in CoL

( FIG. 9)

Pleurotoma aethiopica Thiele, 1925 . 638 m, off Somalia, East Africa   GoogleMaps , 0°27′S, 42°47.3′E. (Expedition Deutschen Tiefsee, st. 253).

Pleurotoma fusiformis Thiele, 1925 . 614 m, Niassüdkanal, 0°15.2′N, 98°08.8′E.

Gemmula thielei Finlay, 1930 . (nom. nov. for Pleurotoma fusiformis Thiele, 1925 ).

† Pleurotoma trincincta Martin, 1935: 113 , pl. 2, figs 2, 2a. Buton Island , south-east Celebes. Oligocene .

† Pinguigemmula okinavensis McNeil, 1960 View in CoL . Okinawa. Japan, Shinzato Tuff Member, Miocene or Pliocene.

Pinguigemmula luzonica Powell, 1964: 278 View in CoL (22–790), pl. 215, figs 3, 4. 326 m, off Hermana, Menor Island, Luzon Island, Philippines.

Pinguigemmula philippinensis Powell, 1964: 278 View in CoL (22–790), pl. 215, figs 5, 6. 512 m, off Santiago, west Luzon Island , Philippines.

Remarks: This species was not included in the study by Puillandre et al. (2012). The protoconch is commonly eroded, with PD = 1.05–1.25 mm, PL = 1.375–1.75 mm and number of whorls ranging from 4.2 to five.

The radula is long, ~ 3.4 mm in length (0.37 of AL), composed of 77 transverse rows of teeth. The marginal teeth are 150–159 µm long (mean 155 µm, N = 5, or 1.66% of AL), duplex. The anterior (inner) 0.4 of the tooth length is solid, narrow in dorsal view, awl shaped; in the posterior part the major and accessory limbs are broadly bifurcating, the accessory limb with a clear constriction and bent at about half tooth length, thin, nearly same length as the major limb. The central formation has a long, narrow, sharp, carinated cusp and lateral flaps with distinct posterior and anterolateral margins. The flaps are not completely fused with the cusp ( Fig. 7E).

The former genus Pinguigemmula is easily distinguishable from Gemmula in having a broadly conical spire, a strongly constricted base and a long, straight siphonal canal ( Powell, 1964). Although expressing a broad variety of forms, the molecular analysis resulted in a single species hypothesis. Several species were described based on the sculptural details, such as the number of gemmate cords (one, two or none). The sculpture seems to be correlated with geography, with the forms from the western Indian Ocean having a smooth intersuture sculpture, whereas the forms from the eastern Indian Ocean to the western Pacific Ocean usually possess two or three gemmate cords. Some large specimens of this species have a similar ‘tertiary notch’ to that of C. praesignis , suggesting sexual dimorphism also for this species ( Kantor & Sysoev, 1991).

List of COI diagnostic sites (position: character state): [115: C; 307: A; 418: G].

Distribution: Found off East Africa to the central Indo-Pacific ( Fig. 4E), from a depth of ~400 to ~ 850 m ( Fig. 5).