Archierato columbella ( Menke 1847 ) 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 : 84-86

Archierato columbella ( Menke 1847) comb. nov.

( Figs. 8 , 16, 17 , 45 )

Erato columbella Menke, 1847: 183 ; Sowerby I, 1859: figs. 31, 32.

Erato leucophaea Gould, 1852: 386 , pl. 14, fig. 20; 1962: 187; Cate, 1977: 361, text fig. 46.

Erato sulcifera Sowerby, 1859 : fig. 3 [preoccupied; non Eratoena sulcifera (Gray in Sowerby I, 1832) ].

? Erato marginata Mörch, 1860: 85 [type lost; never figured].

Hespererato columbella: Schilder,1933: 249 , 254, 262, text figs. 47, 48; 1956: 145, pl. 14, fig. 6; Cate, 1977: 361, text figs. 44, 44d, 44f, (?): 362, text figs. 44c, 44g [subadult?].

Erato (Hespererato) columbella: Keen, 1958: 331 , text fig. 289; 1971: 488, fig. 912; Abbott, 1974: 147.

Neotype. LACM 3302 designated herein. L 6.8 mm, W 4.8 mm, D 3.7 mm, CT 14, LT 12.

Type locality. East side White Port , Palos Verdes Peninsula, Los Angeles County, California, U.S.A. 33°42.8’N 118°18.9’W; intertidal on rocks, ex leg. P.I. LaFollette, 17 January 1969 .

Etymology. From the Latin noun, columbelle, meaning dove.

Diagnosis. Shell large for the genus, 6 to 9 mm long, robust, pyriform, with spaced, slightly irregular, coarse labral and quite irregular, obscured columellar dentition; thickened ventral fold, 14 weak columellar teeth, 12 labral teeth; maximum globosity posteriorly.

Description. Shell large, pear-shaped, somewhat triangular, spire slightly elevated. Suture distinct. Body whorl ~90% of total height, maximum diameter at posterior third, convexly tapered anteriorly. Anterior ventral margin largely indented. Dorsum rounded. Dorsal sulcus absent, with small dimple behind anterior terminal. Whole shell surface covered by thin, sub-glossy callus. Aperture ~ 90% of total height, straight and narrow. Labrum broad, thickened, smooth, flattened ventrally, anteriorly sloping. Outer labral margin rounded, callused, edged at inner margin. Labral teeth coarse, somewhat irregular, 12 in number, restricted to inner labral edge, not extended as folds. Siphonal canal extended, rounded, weakly indented. Anal canal simple, blunt. Columella somewhat sinuous, flattened without inner carinal ridge and obscured parietal lip. Columellar denticles fine, quite irregular, posteriorly somewhat obscured, anterior most extended as thick fold forming terminal ridge. Fossula obscured, flattened, not delimited from columella. Dorsum brown; callosities of ventrum, labral denticles, labral shoulder, columella and fossula, anterior dimple and suture white; labrum orange-brown; anterior tip and tip of anal canal red-brown; first whorls red-brown.

Variability. The shells are more or less inflated and the spire more or less elevated. The dorsum appears pale in dead collected shells but is sometimes covered by white callus. The tips of the canals are sometimes violet-brown. One shell from Cape Tepoca, W Mexico (DFB 1081) has a green-brown dorsum and a pale green-brown labrum, the anterior tip and the protoconch are brown. The strength and appearance of the labral denticles is uniform whereas the columellar denticles are sometimes obscured.

Distribution. Cabrillo Beach, California, U.S.A., to Baja California Sur, Mexico.

Confirmed localities. ‘Bahía Adair, Guayamas [W. Mexico]; Los Arcos, Banderas Bay, Jalisco [W. Mexico]; Cedros Island, W. Baja California [W. Mexico]; Laguna Beach … and Cabrillo Beach, California [ U.S.A.]’ ( Cate, 1977: 362).

Material examined. W. Mexico: Sonora; Cape Tepoca , Sonora ( DFB 1081 ) ; San Carlos Bay, Guaymas ( DFB 5601 ) . U.S.A.: California; Carlsbad, ( DFB 2883 ) ; Encinitas , California ( DFB 5602 ; 5603) .

Remarks. Cate (1977: 362) wrote, “The species group of Hespererato columbella ( Menke, 1847) , H. panamaensis ( Carpenter, 1856) , H. galapagensis Schilder, 1933 [from the E Pacific Ocean and], H. maugeriae ([Gray in] Sowerby II, 1832) and [ H. martinicensis Schilder 1933 from the Caribbean] presents a very difficult problem in separation. There are many reason for simply lumping them together as one species having several indistinct variations ...; yet, color in the anterior canal ..., and outer lip dentition, do illustrate some variation among them.” Truly, the species of the genus Archierato do not present many distinguishing features as Cate mentioned. However, the remaining features help to separate the taxa. First of all the species are geographically restricted and separated. Archierato maugeriae and A. martinicensis are Caribbean species, and there are no reasons to lump them together with the east Pacific taxa as Cate suggested (compare discussion of A. panamaensis , A. maugeriae and A. martinicensis ). Second, it can be observed that the variability in size is quite limited within species that do not exceed 10 mm in length and even more in taxa smaller than 5 mm. Third, the coloration distinguishes them quite easily.

Archierato columbella is one of the most colourful of the recent species. Dead beached shells often lose their bright coloration and can only be distinguished by occurrence, size and shell morphology. Eroded specimens are not usable for the examination of the shell features. The adult shell size of A. columbella is restricted from 6 to 9 mm. The species is found from southern California to both coasts of Baja California, W. Mexico.

Figures

FIGURES 7–9. Archierato type specimens. 7. Archierato maugeriae (Gray in Sowerby I, 1832) lectotype NHMUK 197410/1, L 5.2 mm “Levy County, Florida, U.S.A.” (courtesy H. Taylor). 8. Archierato columbella (Menke, 1847) neotype LACM 3302, L 6.8 mm, White Port, Los Angeles County, California, USA (courtesy L.T. Groves). 9. Archierato panamaensis (Carpenter, 1856) lectotype NHMUK 1966619/1, L 7.5 mm, ‘Pacific Panama’ (courtesy H. Taylor).

FIGURES 16–18. Archierato specimens. 16. Archierato columbella (Menke, 1847) DFB 5603-3, L 5.6 mm, Encinitas, California, USA. 17. A. columbella DFB 2883-2, L 7.3 mm, Carlsbad, California, USA. 18. Archierato cf. panamaensis (Carpenter, 1856), DFB 5604-1, L 7.5 mm, Gobernadora Is, Gulf of Montijo, W Panama.

FIGURES 42–46. Comparison of the E Pacific Archierato species (the shells are equally sized for better comparison, consider, e.g., Tab. 1 for their real dimension). 42. A. michaelmonti, holotype. 43. A. rhondae, holotype. 44. A. panamaensis, lectotype. 45. A. columbella, neotype. 46. A. galapagensis, holotype.