Chama hicksi Valentich-Scott & Coan, new species
Creators: name: Valentich-Scott, Paul
name: Coan, Eugene V.
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Bivalvia
Veneroida
Chamidae
Chama
Chama hicksi

description: Chama hicksi Valentich-Scott & Coan, new species
Figures 1A–E.
Chama sordida Broderip, auctt. non Broderip, 1835.
Bernard (1976: 20–21, in part, figure 6b); Keen (1971: 149, in part, figure 350, right specimen).
Description: Shell shape: subovate; inequivalve, left valve larger; attached by left valve; attachment area moderate in size; right valve sculpture of large, long, irregular spines with commarginal striae, and with dense, short sharp spines over entire surface; left valve sculpture of large, long, irregular spines (with commarginal striae), and fine radial ribs.
Sculpture and color: exterior color variable with shades orange, red and pink; interior color cream, most with exterior color showing through; inner shell margin finely crenulate.
Hinge: hinge plate strong, thick; left valve with one thick, elongate cardinal tooth with roughened surface dorsally, one small elongate posterior lateral tooth with fine tubercles; right valve with one low, elongate cardinal tooth, lateral tooth absent; ligament deeply sunken on a nymph (Figures 1B, E).
Adductor muscle scars: large, subequal, ovate (Figure 1E).
Length: to 40 mm in maximum dimension [SBMNH].
Distribution: In the Gulf of California from Isla Danzante (25.8°N) [SBMNH] to Bahía de los Angeles (29.0°N) [SBMNH], Baja California, and Algodones, Sonora (26.5°N) [SBMNH], to Gulf of Tehuantepec, Oaxaca (16.0 N) [SBMNH], Mexico, 12–75 m [SBMNH]; attached to Spondylus and other shells [SBMNH].
Type specimens and type locality: Holotype SBMNH 358523, length – 28.8 mm, height – 29.5 mm. Type locality: Mexico, Baja California, NE end of Isla Danzante, 60–90 m, attached to Spondylus crassisquama Lamarck, 1819; 25°48'15"N, 111°14'57"W; collected by Hal and Charlotte Norrid, October 1980. Paratype, SBMNH 149294, length – 21.6 mm, height – 29.5 mm, attached to the posterodorsal side of holotype. Paratype, SBMNH 149295, in original type lot (but not attached to other types), length – 14.8 mm, height – 17.0 mm.
Additional paratypes. 8 paratype specimens SBMNH 149297, from Mexico, Baja California, off Punta la Gringa, 20–40 m, attached to mussels; 29°01'56"N, 113°31'11"W; collected by Paul and Carol Skoglund. 2 paratype specimens from same locality BMNH 20100182.
5 paratype specimens SBMNH 83526, Mexico, Baja California Sur, Báhia San Nicolas, 27–29 m; 26°34’42”W, 111°32’18”W; collected by John Fitch, 12 April 1964. 2 paratype specimens from same locality USNM 1135997.
10 paratype specimens SBMNH 83525, Mexico, Baja California, Isla Smith, 31 m; 29°04’30”W, 113°31’00”W; collected by Carl and Laura Shy, May 1976. 2 paratype specimens from same locality CAS 182322.
Etymology: Named in honor of Stephen M. Hicks, for his contributions as Chairman of the Board at the Santa Barbara Museum of Natural History, 2008–2010.
Comparisons: Chama hicksi new species has long been confused with C. sordida Broderip, 1835 (Figure 1 F, G). The later species has a greatly produced, cornucopia-shaped lower (left) valve that is only moderately attached to the substratum, and has short, even spines on the upper valve, along with a few sporadic wider spines (Figure 1 F–J). By contrast, C. hicksi has a short, flattened left valve that is usually fully attached to the substratum, and has a combination of short, dense spines and broad, long, flattened spines.
Chama hicksi new species is closest in shell morphology to C. tinctoria Bernard, 1976. The latter species has shorter spines, the left valve with an interior color of from deep coral red to purple, and a much stronger cardinal tooth in the left valve.
Remarks: Reeve (1846: species 23) illustrated specimens of Chama sordida that do not match Broderip’s original illustrations or description (1835a, b) (Figure 1 F–G). This has led to the confusion as to the identity of this species for over 160 years. Broderip’s original specimens have not been located at BMNH, and Reeve’s illustrated specimens have been incorrectly segregated as syntypes of C. sordida (BMNH 1950.11.1.52–53). Bernard (1976: figure 6a) illustrated the Reeve specimens. Even though the Reeve specimens are from the correct locality, they do not match Broderip’s illustrations (1835b), and are not conspecific with C. sordida. These specimens might represent juvenile C. buddiana Adams, 1852, but further study is necessary to identify the heavily eroded shells.
In order to stabilize nomenclature, we herein designate a neotype for Chama sordida Broderip, 1835 as SBMNH 136149 (Figure 1 H–J), with a type locality of Mexico, Sinaloa, Mazatlán, offshore. We feel that this specimen, and the original specimens in the lot (SBMNH 149296), come close to matching Broderip’s illustration and description. We were unable to find specimens from the original type locality of Isle of Cuna, Panama. Chama sordida is similar to and may be conspecific with Chama corallina Olsson, 1971, but further study, beyond the scope of this paper, is necessary to finalize this hypothesis.
description: Published as part of Valentich-Scott, Paul & Coan, Eugene V., 2010, A new species of Chama (Bivalvia, Chamidae) from Mexico, pp. 65-68 in Zootaxa 2446 on pages 65-67, DOI: 10.5281/zenodo.293938