Galapagos Species Database

Taxon category: Accepted

Syn.: Fissurella macrotrema Sowerby, 1835, F. nigropunctata Sowerby, 1835, Megatebennus cokeri Dall, 1909; AMNH: 20071, 20074, ANSP: 39231, 39234, LACM: n° A.6186.52a, BMNH: 1966387 (Syntypes of Fissurella nigropunctata Sowerby, 1835, type locality: Galapagos). Although having been mentioned by so many authors as occurring in the Galapagos, it seems that neither Fissurella virescens Sowerby, nor the form nigropunctata Sowerby (a synonym), nor macrotrema Sowerby (another synonym) actually occur in the Galapagos. The type locality indicated for Fissurella nigropunctata, showing black crests on the radial ribs, is “Galapagos Isl., and Lobos Isl., under stones on shore”. If it holds true for Lobos Isl. (Peru), the “Galapagos” locality is probably spurious. The only other records of virescens - nigropuncata from the “Galapagos” are in old collections of some museums, without accurate or reliable data, and are therefore dubious (AMNH 20071 & 20074, ex private collection; ANSP 39231 & 39234, ex J.S. Phillips Fund; LACM A.6186.52a, ex Ball collection). No other specimens collected in the Galapagos are known. As for Fissurella macrotrema, the original series of 11 syntypes (BMNH 1966384) was mounted separately in 3 lots, corresponding to the 3 unnamed varieties described by Sowerby from 3 different localities, one of them being the Galapagos (Finet, 1994). The syntypes were not all conspecific, but designation of a lectotype for macrotrema (Finet, 1994) makes it a synonym of F. virescens, with Lobos Isl. as type locality; other conspecific paralectotypes were described as a variety from Lambeyeque. The variety described from the Galapagos (one lot of 3 specimens) was redetermined as F. obscura Sowerby, a true Galapagan species distinct from Fissurella virescens (see Finet, 1994, 1995). The specimen from the Galapagos figured as Fissurella macrotrema by McLean in Keen (1971: fig. 36) (LACM-AHF 178-34) has been tentatively redetermined by McLean (in litt., 1993) as Fissurella cf. obscura (see Finet, 1994). Other specimens from the Galapagos previously identified as F. macrotrema in museum collections have now also been reidentified (LACM: F. obscura, several specimens; USNM 122129: is Fissurella deroyae Mc Lean, 1970). In my opinion, all the foregoing citations of F. virescens, nigropunctata or macrotrema from the Galapagos were based on the original type locality errors being repeated from one author to another, compounded by misidentifications of specimens in museum collections. But there seems to be no further trace of the species on the rocky shores of the Galapagos, and its occurrence there is to be considered spurious or at least dubious. The question was also detailed in Finet (1994 & 1995).

Taxon origin: Native

Distribution: From Mexico, Peru, Panama, Colombia and Galapagos islands.

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