Archierato guadeloupensis, Fehse & Simone, 2020

Fehse, Dirk & Simone, Luiz Ricardo L., 2020, Contributions to the knowledge of the Eratoidae. X. Revision of the genus Archierato Schilder, 1933 (Mollusca: Gastropoda), Zootaxa 4851 (1), pp. 81-110 : 104-106

Archierato guadeloupensis nov. sp.

( Figs. 33−36 )

urn:lsid:zoobank.org:act:4EF880FD-50BB-4906-8463-AEAA233F4C1D

Types. (L, W, D, CT, LT respectivelly). Holotype MNHN IM-2012-4222 : 4.8 by 3.5 by 2.9, 15, 13 ; Paratypes. 1: ZSM Mol 20171204: 4.6 by 3.4 by 2.7, 12, 8; 2: MSF MAM tv15-1: 4.5 by 3.5 by 2.8, 13, 11. USA. Florida; Sarasota, off Longboat Key , DFB 5141 , 9 shells (red algae and sponges, subtidal), DFB 5141-1 : 5.5 by 4.4 by 3.6, 14-11; USA, Florida; Pompano Beach , DFB 5869-1 : 6.3 by 4.7 by 3.7 (Subadult specimen with labral denticles only somewhat developed on the mid-portion) . GUADELOUPE. Port-Louis; Grand Cul-de-Sac Marin, 16°23.3’ N 61°31.8’W MNHN IM-2012-4215 , 1 shell (dredged, 10 m), 16°22.6’N 61°31.7’W, MNHN IM-2012-4217 , 1 shell (dredged, 8 m), 16°21.9’N 61°31.8’W, MNHN IM-2012-4229 ), 1 shell (dredged, 5 m), Vieux Bourg, 16°23’N 061°33’W, MNHN IM-2012-4219 , 1 shell (dredged, 130 m), derrière Ilet Fajou, 16°19.2’N 61°35.3’W, MNHN IM-2012- 4225 , 1 shell(dredged, 6 m), 16°22.7’N 61°35.0’W, MNHN IM-2012-4226 , 1 shell (dredged, 95 m), Passe à Caret, 16°22.3’N 61°38.1’W, MNHN IM-2012-4230 , 2 shells (dredged, 29 m); Basse-Terre, 16°23.7’N 61°32.1’W, MNHN IM-2012-4216 . 4 shells (dredged, 49 m), Pointe Nord Baie de Bouillante , 16°08.5’N 61°47.3’W, MNHN IM-2012- 4220 , 2 shells (dredged, 54 m), Pointe à Lézard, 16°08.4’N 61°46.9’ W, MNHN IM-2012-4228 , 1 shell (dredged, 29 m); Petit Cul-de-Sac Marin, Caye Plate, 16°11.0’N 61°32.4’W, MNHN IM-2012-4232 , 1 shell (dredged, 14 m) .

Type locality. MNHN loc. # GD31 (Expedition Karubenthos 2012), Port-Louis , Grand Cul-de-Sac Marin, 16°25.0’N 61°32.8’W, Guadeloupe; dredged at 85 m.

Etymology. Named after type locality.

Diagnosis. Shell mid-sized, 4 to 6 mm long, robust, rhombic, with widely spaced, coarse labral, obscured columellar dentition; ventral fold thickened, 8 labral, 12 obscured columellar teeth, columellar exceeding labral denticles in number; maximum globosity at posterior third.

Description. Shell mid-sized, rhombic, with elevated spire. Protoconch and subsequent whorls covered by thin callus. Suture slightly indistinct. Body whorl ~80% of total height, maximum diameter in posterior third, convexly tapered anteriorly. Anterior ventral margin widely indented. Dorsum rounded. Dorsal sulcus indicated by a small dimple on anterior terminal collar. Whole shell surface covered by very thin, sub-glossy callus. Aperture comprises ~80% of total height, straight, slightly narrow. Labrum narrow, ventrally convex, thickened, smooth, rounded ventrally, slightly declivous anteriorly. Outer labral margin rounded, callused, edged at inner margin. Labral teeth coarse, widely spaced, 13 in number, continued as quite short, coarse folds. Siphonal canal short, left turned, rounded, blunt. Anal canal simple, blunt. Columella straight, flattened without inner carinal ridge, slightly developed parietal lip. Columellar denticles rather obscured, quite fine (only visible under higher magnification), special lateral view, 15 in number, exceeding labral denticles in number, anterior most forming terminal ridge, posterior most enlarged, projecting. Fossula obscured, not delimited from columella. Callosities white; labrum light whitish-brown; dorsum light green-brown; tips of canals and protoconch and first whorls green-brown.

Variability. The shells are more or less inflated and the spire more or less elevated. The labral denticles are irregularly developed but always coarse and widely spaced. The coarse, widely spaced dentition is already visible in subadult specimens.

Distribution. Florida to Guadeloupe.

Remarks. Archierato guadeloupensis is the third colourful taxon within the genus and is similar to A. maugeriae . It is easily distinguished from the latter by the coarse, widely spaced labral denticles, the columellar denticles exceed the labral in number, the straight aperture and columella, the sloped anterior labral portion and the leftturned siphonal canal. The new species is separated from A. columbella and A. panamaensis as described for A. maugeriae (see discussion above).

Archierato guadeloupensis is immediately distinguishable from A. martinicensis by the rhomboidal instead of sub-triangular shell outline, the colored shell, the coarse, widely spaced labral denticles, the dorsal dimple on the anterior terminal collar and the left turned siphonal canal.

Archierato guadeloupensis differs from A. janae in lacking the angular shell outline and by the coarse, widely spaced labral denticles, the left turned siphonal canal and the straight columella, the simple yellow-green colouration, the oblique whorls, the inflated shell, the higher dorsal profile, the lower apex, the dorsal dimple on the anterior terminal collar and the posteriorly projected labrum.

The new taxon is distinguished from A. dalli by the subtriangular shell outline with maximum width in the posterior quarter. The outline of the latter is obliquely pear-shaped with maximum diameter in the posterior third. The labral denticles of A. guadeloupensis are coarser and less numerous (8 to 11 in guadeloupensis vs. 12 to 16 in dalli ) and they are extended as essentially coarser folds. The labrum is flattened in the new species but rounded in A. dalli . In the latter the anal canal is turned much more to the left, and the posterior labral portion is more projected. Archierato guadeloupensis is also separated from A. dalli by the dorsal dimple on the anterior terminal collar.

Figures

FIGURES 33–35. Archierato guadeloupensis n. sp type specimens. 33. Holotype MNHN 2012-4222. L 4.8 mm, Port-Louis, Grand Cul-de-Sac Marin, Guadeloupe. 34. Paratype 3 DFB 5141-1, L 5.7 mm, off Longboat Key, Sarasota, Florida, USA. 35. Paratype 4 DFB 5869-1, L 5.7 mm, Pompano Beach, Florida, USA.

FIGURES 36–41. Comparison of the W Atlantic Archierato species (the shells are equally sized for better comparison, consider, e.g., Tab. 1 for their real dimension). 36. A. guadeloupensis, holotype. 37. A. dalli, holotype. 38. A. dalli, off Florianópolis, Santa Catarina State, Brazil. 39. A. martinicensis, holotype. 40. A. maugeriae, lectotype. 41. A. janae, holotype.