Archierato dalli (Morretes, 1941), 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 : 90-91

Archierato dalli (Morretes, 1941) (revalidated)

( Figs. 23 , 27–29 , 38 )

Persicula dalli Morretes, 1941: 252 (pl. 1, figs. 4−7); Rios 1975: 71 (in syn), 1985: 63 (in syn), 1994: 78 (in syn); 2009: 139 (in syn).

Erato maugeriae: Abbott, 1954: 176 (pl. 22, fig. w); Rios, 1970: 59; 1975: 71 (fig. 290); 1985: 63 (fig. 279); 1994: 78 (fig. 300); 2009: 139 (fig 331) (non Gray in Sowerby I, 1832).

? Hespererato maugeriae: Tunnel et al., 2010: 175 (fig.) (non Gray in Sowerby I, 1832).

Holotype. MZSP 10627 . L 4.5 mm, W 2.7 mm, CT 12, LT 15.

Type locality. Between Bertioga and Santos, São Paulo State, Brazil.

Etymology. Named for William Healey Dall.

Diagnosis. Shell mid-sized, 4 to 6 mm long, robust, inflated pyriform, with close-set, coarse, quite irregular labral, obscured columellar dentition; ventral fold thin, 12 labral, 12 columellar teeth; maximum globosity at posterior third.

Description. Shell mid-sized, inflated pear-shaped, with elevated spire. Protoconch and subsequent whorls covered by thin callus. Suture slightly indistinct. Body whorl ~80% of total height, maximum diameter at posterior third, quite convexly tapered anteriorly. Anterior ventral margin indented. Dorsum rounded. Dorsal sulcus absent. Whole shell surface covered by very thin, sub-glossy callus. Aperture ~75% of total height, sinuous and somewhat widened. Labrum narrow, curved in profile, thickened, smooth, rounded ventrally, anteriorly declivous. Outer labral margin rounded, callused, edged and straight at inner margin. Labral teeth coarse, less developed, close-set, irregular, 12 in number, continued as slightly coarse, short folds. Siphonal canal short, rounded and protruded. Anal canal simple, indented. Columella sinuous, curved without inner carinal ridge, slightly developed parietal lip. Columellar denticles 12 in number, somewhat obscured, irregular, coarse, spaced, anterior most forming terminal ridge, posterior most enlarged, projecting. Fossula obscured, not delimited from columella. Callosities pale brownish-white; apex and dorsum reddish-brown.

Variability. The shells are more or less inflated. The elevation of the spire varies considerably. The posterior labral portion is more or less projected. Live-collected specimens are pale and uniformly colored. Juvenile and subadult (see paratype 1) specimens show a fairly wide aperture because the labrum is not yet developed. The folds at the declivous part of the labrum is a quite constant feature found at all examined specimens.

Distribution. Roatan, E Honduras, to Guarapari, Brazil.

Examined material. Holotype. Brazil: Guarapari, Espirito Santo State ( DFB 5865 ). E Honduras: Guanajas, Roatan ( DFB 5867 ). E Panama: Bocas Toro , Gulf of Mosquito ( DFB 5866 ). Venezuela: Maiquetía , Federal District ( DFB 5868 ).

Remarks. Archierato dalli is distinguishable from A. maugeriae , of which it has been considered a synonym, by the simple coloration, the curved aperture, the posteriorly projected labrum, the slightly developed fossula with a roundly callused inner fossular margin, the indistinct or obscured columellar dentition, the extended declivous labral portion with anterior labral denticles slightly extended a short folds, the almost straight columella and the bulbous shell.

Similarly, A. dalli differs from A. martinicensis by the bulbous shell, the curved aperture, the posteriorly projected labrum, the slightly developed fossula, the oblique apex and the extended declivous portion of the labrum with the short folds anteriorly.

Archierato dalli is readily separated from A. janae in lacking the angular shell outline on first sight. Archierato dalli is, furthermore, distinguishable from A. janae by the reddish-brown instead of green shell coloration. The shell of A. dalli is already somewhat inflated in comparison to A. martinicensis and A. maugeriae but A. janae appears even broader—although the ratio of width to length is similar—and is already visible in the whorls of the apex. The aperture and labrum of A. dalli are slightly narrower and curved and the declivous labral portion is more extended. The posterior labral denticles are coarser, more distant, prominently and projected in A. janae and the anterior denticles are not extended. The inner labral edge is somewhat protruded at mid-portion in A. janae and appears, therefore, slightly broader.

Tunnel et al. (2010: 175, 1 unnumb. text fig.) showed a shell of unknown origin but most probably from the Gulf of Mexico. The shell slightly resembles the Brazilian A. dalli and is provisionally assigned to the latter because no such shell could be examined.

One specimen of the type lot of A. dalli resembles A. janae somewhat because the shell is not yet fully matured and is also somewhat eroded because of its beached condition. The callosity is only slightly developed and is especially visible by the posterior labral portion. However, the reddish-brown color is identical to the holotype. This shell does not represent A. dalli well because the somewhat abnormal appearance and is a good example that a safe identification of Eratoidae is only more secure by fully matured shells only. Species based on juvenile specimens could be considered as nomen dubia ( Fehse 2013).

Figures

FIGURES 21–23. Archierato type specimens. 21. Archierato martinicensis (Schilder, 1933) holotype NMW 1955.158.01218, L 4.5 mm, Martinique, Lesser Antilles, Windward Island (courtesy: H. Wood). 22. A. martinicensis paratype CS 3611, L 4.7 mm (same place). 23. Archierato dalli (Morretes, 1941) holotype MZSP 10627 L 4.5 mm, between Bertioga and Santos, São Paulo State, Brazil.

FIGURES 27–29. Archierato dalli (Morretes, 1941) specimens. 27. DFB 5840, L 6.3 mm, off Florianópolis, Santa Catarina State, Brazil. 28. DFB 5865, L 5.2 mm, off Guarapari, Espirito Santo, Brazil. 29. slightly subadult, DFB 5866, L 4.1 mm, Bocas Toro, Gulf of Mosquito, 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.