Archierato janae, 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 : 97-104

Archierato janae nov. sp.

( Fig. 30−31 , 41 )

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Types. (L, W, D, CT, LT respectivelly). Holotype ZSM Mol 20171203: 5.7 by 4.7 by 3.8, –, 16; Paratypes: 1: MSF MAM tv14: 6.3 by 5.0 by 4.0, –, 16; 4 DFB (5843) from type locality. COSTA RICA. 1 DFB (7653), Plio-Pleistocene of Limon Hill,: 4.9 by 3.8 by 3.1, –, 12. E PANAMA. San Blas Island , DFB 5907 , 4 shells. GUADELOUPE. Baie de Baille-Argent , Basse-Terre, 16°15.6’N 61°48.8’W, 40 m , MNHN IM-2012-4221 , 1 shell (dredged GD210, GD21; Vieux Bourg, Grand Cul-de-Sac Marin, 16°22.8’N 61°33.4’W, 60 m, ZSMMNHN ( IM-2012-4223 ), 1 shell (dreded, GD370; Ilet Gosier, Petit Cul-de-Sac Marin, 16°11.3’N 61°30.0’W, 22 m, MNHN IM-2012-4224 , 1 shell (dredged, GD50 ); banc des Vaisseaux, Grande-Terre, 16°09.0’N 61°17.3’W, 33 m, MNHN IM-2012-4227 , 1 shell (dredged, GD68 ). BRAZIL. Espírito Santo; off Guarapari , 6 DFB (6363), DFB 6363-1 : 6.8 by 5.4 by 4.2, –, 16.

Type locality. off Hypoluxo , Florida, U.S.A. (26°33’N 80°00’W), dredged at 91 m, 1980 .

Etymology. Named for Jana Kratzsch, contributor of the Molluscan Science Foundation, for her kind support of my studies on Eratoidae .

Diagnosis. Shell mid-sized, 5 to 7 mm long, robust, angular pyriform, with close-set, coarse, somewhat obscured labral and obscured columellar dentition; ventral fold fine, 16 labral teeth; maximum globosity at posterior third.

Description. Shell mid-sized, angularly and obliquely pear-shaped, spire elevated. Protoconch and subsequent whorls covered by thin callus. Suture distinct. Body whorl almost 90% of total height, maximum diameter at posterior third, quite convexly tapered anteriorly. Anterior ventral margin largely indented. Dorsum roundly edged. Dorsal sulcus absent. Whole shell surface covered by very thin, sub-glossy callus. Aperture comprises ~90% of total height, sinuous and narrow. Labrum narrow, largely curved in profile, thickened, smooth, rounded ventrally, anteriorly declivous. Outer labral margin rounded, callused, edged and almost straight at inner margin. Labral teeth coarse, less developed, close-set, irregular, 16 in number, slightly continued as coarse folds. Siphonal canal short, rounded and slightly indented. Anal canal almost well shaped, indented. Columella sinuous, curved without inner carinal ridge and slightly developed parietal lip. Columellar denticles obscured, anterior most forming terminal ridge. Fossula obscured, inner fossular edge callused, not delimited from columella. Labrum and anal canal white; ventrum and fossula pale white-brown; dorsum, apex and anterior tip pale yellow-brown.

Variability. The shells are more or less inflated and the spire more or less elevated. The labral denticles are more or less prominent but always uniform in strength. Otherwise the shells vary only slightly.

Distribution. Costa Rica to Espírito Santo, Brazil.

Remarks. The angular shell outline easily separates Archierato janae from A. maugeriae . Further differences are the simple yellow-green coloration, the oblique whorls, the inflated shell, the obscured columellar dentition, the higher dorsal profile, the lower apex, the anterior ventral margin more indented and the posteriorly projected labrum.

The angular shell outline distinguishes A. janae and A. martinicensis . Both possess a simple coloration but the new species is separated by the oblique whorls, the essentially more inflated shell, the higher dorsal profile, the posteriorly projected labrum and the wider shell (ratio of width to length is 82% in janae vs. 60% in martinicensis ).

One shell from off Guarapari (DFB 6363) resembles the specimens from Hypoluxo in the overall shell morphology but differs by its light yellow-brown instead of the vivid green shell coloration. The variation of the shell coloration might be intraspecific and, therefore, this specimen is assigned to A. janae based especially on the remaining morphology.

The few available shells from off San Blas Island, E. Panama are somewhat unusual in their small size of 3.5 to 4.6 mm and might represent either a dwarf population or even a new species.

Figures

FIGURES 30–32. Archierato specimens. 30. Archierato janae nov. sp. holotype ZSM 20171203. L 5.7 mm, off Hypoluxo, Florida, S.A. 31. A janae paratype MSF MAM tv14, L 6.3 mm, off Hypoluxo, Florida, USA. 32. Archierato maugeriae (Gray in Sowerby I, 1832) DFB 7466, L 4.9 mm, Charao Azul, E Panama.

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.