Sinezona carolarum, Geiger, Daniel L. & Mclean, James H., 2010

Geiger, Daniel L. & Mclean, James H., 2010, New species and records of Scissurellidae and Anatomidae from the Americas (Mollusca: Gastropoda: Vetigastropoda), Zootaxa 2356, pp. 1-35 : 8-11

Sinezona carolarum n. sp.

Figures 5–8

Sinezona n. sp. Geiger, ms: Kaiser, 2009: 221, 228, fig. 237 I–K [paratype Fig. 7 B].

Type material. Holotype ( SBMNH 83703 ) . Paratypes: type locality ( SBMNH 83704, 2); 16–23 m, Isla Maria Cleofa, Islas Tres Marias, Mexico, 21.300˚N, 106.276˚W ( SBMNH 83705, 4, mounted radula); 23–30 m, Sharkfin Rock, SSW Punta Rodriguez, Isla del Coco, Costa Rica, 5.533˚N, 86.983˚W ( SBMNH 83706, 3); 12–15 m, Clipperton Island, France, 10.305˚N, 109.198˚W (KKC 210001, 8); 12–15 m, 10.305˚N, 109.198˚W ( LACM 3116, 5; MNHN 21265, 5; SDMNH, 5; WAM S41348 , 5; USNM 1117767, 5; all ex KKC 200518). 10–38 m, Clipperton Island, France, 10.320˚N, 109.223˚W ( SBMNH 83707, ex KKC 210111, 2).

Type locality. 15–30 m, East side, Clipperton Island , France, 10.295˚N, 109.201˚W, leg. Kirstie Kaiser.

Additional material examined. France, Clipperton Island. 12–15 m, 10.305˚N, 109.198˚W (KKC 200518, 75). 11–22 m, 10.316˚N, 109.214˚W (KKC 210048, 5). 17 m, NW side, 10.322˚N, 109.223˚W (KKC 210108, 1). 15–30 m, East side, 10.295˚N, 109.201˚W (KKC 200516, 51). 12–43 m, 10.291˚N, 109.225˚W (KKC 200517, 80). 10–38 m, 10.320˚N, 109.223˚W (KKC 210047, 8). 15–20 m, 10.314˚N, 109.238˚W (KKC 210000, 12). 69 m, 10.320˚N, 109.235˚W (KKC 200515, 47). 15 m, 10.288˚N, 109.350˚W (KKC 200519, 40).

Costa Rica. 23–30 m, Sharkfin Rock, SSW Punta Rodriguez, Isla del Coco, 5.533˚N, 86.983˚W (KKC, 5). Mexico. 16–23 m, Isla Maria Cleofa, Islas Tres Marias, 21.300˚N, 106.276˚W (KKC, 7).

Etymology. Named after Carole Hertz, editor of The Festivus, and Carol Skoglund, long time collector and student of the Panamic molluscan fauna, for their significant body of work and often collaborative efforts to better understand the taxonomy of the Panamic fauna. Genitive feminine plural of their common first name.

Description. Shell small (to 0.54 mm), trochiform. Protoconch of 0.875 whorls, fine axials on outer portion of whorl, weak apertural varix not connected to embryonic cap, apertural margin straight. TI of 0.8– 1.1 whorls, with 15–38 axial cords, interstices with fine irregular growth marks, first spiral thread no earlier than after 0.66 whorls, increasing to 0–2 on shoulder, approximately six between position of selenizone and periphery. TII of 0.33 whorls. Shoulder almost flat, axial cords of same density as on TI, two to five indistinct spiral lines. Base with moderate constriction below selenizone, axials as on shoulder, approximately 12 spirals, increasing in strength from lines at periphery to low cords near umbilicus, sometimes forming diffuse nodules at intersection with axials. Umbilicus open, bordered by moderately strong spiral cord, walls straight, with fine axial growth marks. Selenizone slightly above periphery, keels low, strong, growth marks distinct, selenizone approximately twice as long as teardrop shaped foramen. Aperture subquadratic, roof overhanging.

Radula, rachidian triangular with five denticles of cusp, central one largest, denticles arranged in V. Lateral teeth 1–3 similar, three to four denticles on outer edge of cusp. Lateral tooth 4 reduced, hook-shaped. Lateral tooth 5 enlarged by broadening, six denticles on inner margin of cusp. Radular interlock of central field moderate. Inner marginal teeth with terminal denticle largest, one on inner edge, four on outer edge. Outer marginal teeth spoon-shaped with many denticles on either side of cusp.

Differential diagnosis. Sinezona rimuloides (Carpenter, 1856) from the Panamic province to central California is more elevated in overall shape, has a narrower umbilicus, and the selenizone is approximately three times as long as the foramen.

Distribution. Mexico (offshore Isla Maria Cleofa), Clipperton and Cocos Islands.

Figures

FIGURE 5. Holotype of Sinezona carolarum n. sp. 15 – 30 m, East side, Clipperton Island, France, 10.295 ˚ N, 109.201 ˚ W (SBMNH 83703). Scale bar shell = 500 µm. Scale bar protoconch = 100 µm.

FIGURE 6. Paratypes of Sinezona carolarum n. sp. A. 12 – 15 m, Clipperton Island, France, 10.254 ˚ N, 109.198 ˚ W (KKC 2100001, 8). B. Juvenile with still open slit. 10 – 38 m, Clipperton Island, France, 10.320 ˚ N, 109.223 ˚ W (SBMNH 83707). C. 16 – 23 m, Isla Maria Cleofa, Islas Tres Marias, Mexico, 21.300 ˚ N, 106.276 ˚ W (SBMNH 83705). Scale bar shell = 500 µm. Scale bar protoconch = 100 µm.

FIGURE 7. Paratypes of Sinezona carolarum n. sp. A – B. 15 – 30 m, East side, Clipperton Island, France, 10.295 ˚ N, 109.201 ˚ W (SBMNH 83704, 2). C. 23 – 30 m, Sharkfin Rock, SSW Punta Rodriguez, Cocos Island, Costa Rica, 5.533 ˚ N, 86.983 ˚ W (SBMNH 83706, 3). Scale bar shell = 500 µm. Scale bar protoconch = 100 µm.

FIGURE 8. Radula of Sinezona carolarum n. sp. 16 – 23 m, Isla Maria Cleofa, Islas Tres Marias, Mexico, 21.300 ˚ N, 106.276 ˚ W (SBMNH 83705). A. Entire radula. Scale bar = 100 µm. B. Full width of radula enlarged with separated tooth elements. Scale bar = 10 µm.