Lamellilatirus boucheti, Lyons & Snyder, 2019

Lyons, William G. & Snyder, Martin Avery, 2019, Fasciolariidae (Gastropoda: Neogastropoda) of French Guiana and nearby regions, with descriptions of two new species and comments on marine zoogeography of northeastern South America, Zootaxa 4585 (2), pp. 239-268 : 257

Lamellilatirus boucheti new species

( Figures 22–26 )

Types. Holotype, dd, 23.1 mm (IM-2013-56530), GUYANE sta. CP 4381, French Guiana , 06°31’N, 52°26’W, 114–118 m, 0 4 Aug 2014 . Paratypes: 1-dd, 19.1 mm ( ANSP 473538 ), GUYANE sta. CP 4380, 06°31’N, 52°27’W, 102–104 m, 0 4 Aug 2014 ; 1-lv, 19.1 mm (IM-2013-56531), GUYANE sta. CP 4381 (type locality, above); 1-dd, 22.5 mm, IM-2014-6649, GUYANE sta. CP 4382, 06°27.8’N, 52°25.5’W, 93–95 m, 0 4 Aug 2014 .

Type locality. Continental shelf off French Guiana, northeastern South America, 06˚ 31’N, 52˚ 26’W, 114–118 m.

Description. Shell small for genus, to 23.1 x 9.9 mm, fusiform, slender, with prominent axial ribs, spiral cords of subequal size and abundant subsutural lamellae. Protoconch of 2 elevated, glassy whorls, first whorl smooth, subglobose and with immersed tip; second whorl slightly wider, with 2 or 3 very faint axial riblets near junction with teleoconch. Teleoconch of 7 whorls, each with 7 or 8 loosely aligned, well-developed axial ribs crossed by spiral cords; 3 subequal cords on whorls 1–3, increasing by intercalation to about 6 on penultimate whorl, usually separated by single faint spiral threads; 2 medial cords larger on whorls 4 and 5, diminishing in relative size on penultimate whorl. Body whorl with broadly rounded axial ribs and about 10 spiral cords; cords most prominent where crossing ribs, each cord separated from others by about 3 faint threads. Suture deeply impressed, slightly undulating, bordered anteriorly by sutural ramp bearing many prominent, scale-like lamellae. Base with about 6 rather small cords, tapering rapidly to short, slender siphonal process; 9 or 10 thin, oblique cords continuing to tip of process. Aperture subovate, outer lip arched adapically, shallowly crenulate at edge, inner surface bearing 12–14 straight, continuous lirae; columella smooth, nearly straight anteriorly, arched posteriorly with small node on parietal shield, node subsumed by thickened callus on largest specimen. Shell exterior orange brown, with lighter cream band near anterior edge of body whorl; some cords also tinged with cream where crossing ribs on penultimate and body whorl; aperture light tan. Operculum obliquely ovate, slightly hooked, tapering to anterior nucleus; outer surface bearing many faint growth increments, inner surface with thick callus around entire circumference; color light tan, nearly transparent.

Etymology. The species name honors Dr. Philippe Bouchet, principal investigator for the marine component of the GUYANE expedition, who made the material available to us for study.

Distribution. Known only from continental shelf off French Guiana, depth 93– 118 m.

Remarks. Lamellilatirus boucheti n. sp. is represented by four specimens from three stations, including two stations that yielded L. corrugatus ; holotypes of both species are from the same station. The presence of two sympatric species of Lamellilatirus off French Guiana is surprising, but their shells are so dissimilar that no other explanation seems likely. The body whorl and spire of shells of L. boucheti have more numerous cords of more modest size compared to the three or four much larger cords of L. corrugatus ; mature shells of L. boucheti have 12–14 distinct, entire lirae on the inside of the outer lip, whereas L. corrugatus has only six or seven less distinct, sometimes interrupted lirae; and shells of L. boucheti display a pale band at the anterior edge of the body whorl, whereas shells of L. corrugatus are uniformly orange-brown. A pale band also occurs on the body whorl and later whorls of the spire of L. lamyi , but that band is situated near the middle of each whorl, whereas the band on L. boucheti occurs only at the anterior edge of the body whorl and does not occur on whorls of the spire. Spiral cords are also more slender and widely spaced on shells of L. lamyi than on shells of L. boucheti .

Figures

FIGURES 17–38. Guianas Peristerniinae. 17–21. Lamellilatirus corrugatus n. sp. 17–19. Holotype, 30.5 mm, CP4381, 06°31’N, 52°26’W, depth 114–118 m, MNHN IM-2013-56529. 20–21. Paratype, 23.8 mm, CP 4380, MNHN IM-2012-20355; ANSP 473537. 22–26. Lamellilatirus boucheti n. sp., 22–24. Holotype, 23.1 mm, CP4381, 06°31’N, 52°26’W, depth 114–118 m, IM-2013-56530. 25–26. Paratype, 19.1 mm, same date as holotype, IM-2013-56531; ANSP 473538. 27–28. Polygona bernadensis (Bullock, 1974), 46.4 mm, CP 4402, 06˚18’N, 52.˚13.3’W, depth 95–97 m, MNHN IM-2013-56853. 29–38. Polygona lactea (Matthews-Cascon et al., 1991). 29–30. Holotype, 27 x 11 mm, Almirante Saldanha, sta. 1767, off Pará, Brazil, 01°32’05”N, 47°24’05”W, depth 63 m, MNRJ 6201. 31–32. Paratype, 18 x 8 mm, same data as holotype, CMPHRM- 668B. 33–34. Paratype, 32 x 14 mm, Almirante Saldanha sta. 2441, off Pará, 01°46’N, 47°14’W, depth not stated, CMPHRM- 1031B. 35–38. 25.5 and 29.5 mm, CP4352, 05°13.9’N, 51°41.7’W, depth 60 m, MNHN IM-2014-6078.