Lamellilatirus corrugatus, 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 : 255-257

Lamellilatirus corrugatus new species

( Figures 17–21 )

Lamellilatirus lamyi: Couto et al., 2016: 311 , 314, 315 (French Guyane); Kantor et al., 2018: 14; non Lamellilatirus lamyi Lyons & Snyder, 2013 (Martinique) . Lamellilatirus sp. Kantor et al., 2018: 4 ( GUYANE 2014, specimen IM 2013-56511).

Types. Holotype 30.5 mm, lv (IM-2013-56529), GUYANE sta. CP 4381, French Guiana , 06°31’N, 52°26’W, 114–118 m, 0 4 Aug 2014 . Paratypes: 2-lv, 22.7 mm (IM-2013-56510) and 23.2 mm ( IM 2013-56511 ), 1-dd, 23.8 mm ( ANSP 473537 ), all from GUYANE sta. CP-4380, French Guiana , 06°31’N, 52°27’W, 102–104 m, 0 4 Aug 2014 .

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

Other material. French Guiana— 1-dd, 28.1 mm (IM-2012- 220353), GUYANE sta. CP 4402, 06°18’N, 52°13.3’W, 95–97 m, 0 8 Aug 2014.

Description. Shell small for genus, to 30.5 x 13.6 mm, with prominent axial ribs, strong spiral cords and abundant subsutural lamellae. Protoconch of nearly 2 elevated glassy whorls, first whorl smooth, flattened, with immersed tip; secord whorl scarcely wider than first, with flat sides and 4 or 5 rather robust axial riblets near junction with teleoconch. Teleoconch of about 7 whorls, each with about 6 large, unaligned, broadly rounded axial ribs extending from suture to suture; whorls 1–3 with 3 subequal spiral cords; whorls 4–6 with 4 thick, elevated cords with rounded tops; cords wider where crossing ribs, separated from each other by 3–5 faint spiral threads; interspaces between cords deep, channel-like. Body whorl wider than long, with 3 or 4 prominent cords crossing axial ribs and flanked anteriorly and posteriorly by 1 or 2 lesser cords, all separated by fine threads. Suture deeply impressed, slightly undulating, bordered anteriorly by sutural ramp bearing many scale-like lamellae; similar lamellae scattered irregularly across shell surface at edges or previous growth increments. Base with 4 or 5 thin spiral cords, narrowing abruptly from body whorl, tapering to short, slender siphonal process; 12 to 14 thin, oblique cords and threads continuing to tip. Aperture subovate, slightly constricted at anterior and posterior ends; outer lip rendered slightly crenulate at edge by termini of external cords, inner surface bearing 6 or 7 narrow lirae, 2 or 3 nearest entrance to siphon interrupted, others entire; inner lip slightly detached, extending more than half distance to tip along inner edge of siphon; columella straight anteriorly, curved posteriorly to merge with thick parietal callus; siphon smooth, sinuose. Shell exterior entirely orange-brown, without bands or patches of different hues; interior white. Operculum obliquely ovate, slightly hooked, tapering to anterior nucleus; outer surface covered with closely-packed, concentric growth increments; inner surface with narrow callus around perimeter and several narrower concentric rings within; color orange, nearly transparent.

Etymology. The specific name, an adjective, from Latin noun ruga, meaning wrinkle or ridge, and the suffux - atus, meaning provided with, in reference to the ridge-like cords that encircle the shell.

Distribution. Known only from continental shelf off French Guiana, depth 102– 118 m.

Remarks. Lamellilatirus corrugatus n. sp. is represented by five specimens taken at three stations. The relatively few cords on the spire and body whorl are exceptionally tall and robust and confer a channeled appearance to spaces between the cords, an effect unique among species of Lamellilatirus . The new species somewhat resembles L. lamyi Lyons & Snyder, 2013 from off Pointe de la Caravelle, Martinique, depth 250 m, but may be distinguished by its channeled sculpture of ridge-like cords and its lack of a prominent, pale band on the spire and body whorl, the latter a feature characteristic of L. lamyi . See next species account for comparisons with another Lamellilatirus species from French Guiana.

The specimen reported as Lamellilatirus lamyi by Couto et al. (2016) in their study of fasciolariid molecular phylogeny (IM-2013-56511) is a paratype of L. corrugatus . The earlier name was assigned during preliminary sorting and was not corrected before being sampled by Couto et al.

The holotype was taken during a growth episode, so its outer lip is thin, its inner surface is nearly smooth, its inner lip is barely developed, and color within the aperture matches that of the external teleoconch. Consequently, descriptions of those features were taken from paratypes.

The 23.2 mm paratype has an apparently complete drill hole near the tip of the spire, but the shell retains the dried animal, indicating that the attack was unsuccessful.

The specimen from sta. CP 4402 has the appearance of a dead shell long buried in mud. Most of the color has been leached away, and details of microsculpture are eroded. Although not as pronounced as on typical specimens, the primary spiral cords on the body whorl are few and relativey large, so we tentatively assign the shell to L. corrugatus .

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.