File:American malacological bulletin (1988) (17970068919).jpg

Title: American malacological bulletin
Identifier: americanmal6719881990amer (find matches)
Year: 1983 (1980s)
Authors: American Malacological Union
Subjects: Mollusks; Mollusks
Publisher: (Hattiesburg, Miss. ?) : (American Malacological Union)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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102 AMER. MALAC. BULL. 6(1) (1988)
Text Appearing After Image:
Figs. 100-104. Acanthochitona balesae Abbott, 1954. Intermediate valves of disarticulated paratype of A. interfissa Kaas, 1972; Malmok, Arasji, Aruba; RMNH 4502. Length of largest valve (Fig. 100) 1.6 mm, including sutural laminae. colored spicules; 18 anterior and sutural tufts comprised of about 50 straight, slender, sharp-tipped, vitreous spicules up to 700 long; margin fringed with straight, slender, sharp- tipped spicules 250-280 /im long; underside evenly covered with short (50-60 /tm), straight, sharp-tipped spicules directed toward periphery. DISCUSSION: Several names have been proposed for this species. Pilsbry (1940) illustrated without text a chiton he called Acanthochitona balesae from Bonefish Key, Florida, thereby creating a nomen nudum. Abbott (1954) included A. balesae 'Pilsbry 1940' from Bonefish Key, with brief differential diagnostic remarks. Kaas (1972) recognized the nude status of Pilsbry's name; to rectify that problem, he described four specimens from Bonefish Key (RMNH) and named them A. elongata. In the same paper, Kaas named A. interfissa from Trinidad and Aruba and noted similarities between that species and A. elongata. Abbott (1974) included A. balesae 'Pilsbry' Abbott, repeated his diagnostic comments, and stated that A. elongata was a synonym. Bullock (1974) pointed out that Kaas "overlooked the fact that Abbott ... validated Pilsbry's name, and A. elongata Kaas must be considered a junior synonym of A. balesae 'Pilsbry' Abbott." Bullock also remarked that the relationship between A. interfissa and A. balesae should be investigated. Watters (1981) relegated both A. elongata and A. interfissa to the synonymy of A. balesae and designated a lectotype (ANSP 349331; Bonefish Key) for A. balesae. Ferreira (1985) incorrectly stated that Abbott (1974) regarded A. balesae to be a synonym of A. elongata. Ferreira clearly considered Abbott's diagnosis inadequate and without priority over A. elongata. He agreed with Watters that A. interfissa is a synonym of A. elongata, but he also relegated A. andersoni Watters, 1981, to the synonomy of A. elongata. Finally, Ferreira declared all the above taxa to be juveniles and secondary synonyms of Choneplax lata (Guilding, 1829). The International Code of Zoological Nomenclature re- quires that, to be available, a species name introduced after 1930 must be accompanied by a description or definition that states in words characters that are purported to differentiate the taxon (Article 13(a)(i); ICZN, 1985). Abbott's (1954) account of Acanthochitona balesae, although brief, addressed size, proportions, pustule morphology, shape and ornamentation of the jugum, and a location where the species occurs; some characters were compared with those of A. pygmaea. Such treatment satisfies the requirements of ICZN Article 13, so A. balesae Abbott, 1954, is valid, and A. elongata Kaas, 1972, is a junior synonym. I examined the holotype and three of the four paratypes of Acanthochitona interfissa Kaas and the holotype and seven paratypes of A. andersoni Watters. I found no characters upon which to separate the holotype and paratypes of A. interfissa from topotypic specimens of A. balesae from Bonefish Key, so I cannot refute contentions by Watters (1981) and Ferreira (1985) that A. interfissa is a synonym of A. balesae. However, A. andersoni is not a synonym of A. balesae, and neither name is a synonym of Choneplax lata. Several problems are associated with the original description and type series of Acanthochitona interfissa. Kaas reported the holotype and a paratype from Trinidad and three paratypes from Aruba. He reported that he disarticulated and illustrated the paratype from Trinidad. However, although the valves and spicules of that specimen now are almost totally dissolved in preservative, the specimen is intact, as is the holotype. One of the Aruba paratypes has been disarticulated. Five of the valves remain (Figs. 100-104), but valves i, viii, and an intermediate valve are missing; none of the valves resembles the curiously misshapen valve ii illustrated by Kaas. Except for valve viii, the description and illustrations of valves of Acanthochitona interfissa (Kaas, 1972: figs. 95-101) seem indistinguishable from those of A. balesae. Valve viii of A. interfissa as illustrated by Kaas (his figs. 95-97) differs from the corresponding valve of A. elongata (= A. balesae) (Kaas, 1972: figs. 90, 91) by tegmental shape, pustule con- figuration and size, jugal length and expansion, by possession of a greatly flared insertion plate and laminae, and most notably, by possession of a medial third slit in the posterior insertion plate. Conversely, valves i, ii, and iv of A. interfissa (Kaas, 1972: figs. 98-101) are indistinguishable from those of A. balesae whose corresponding valves Kaas described but did not illustrate in the account of A. elongata which immediately preceded that of A. interfissa. Ferreira (1985) could have been prompted to combine Acanthochitona andersoni with A. interfissa because of Kaas' description of valve viii of the latter. Among the Caribbean Acanthochitona species, valve viii of A. interfissa as illustrated by Kaas most resembles that of A. andersoni, if the third slit of A. interfissa is ignored. I found a single specimen of A. andersoni among three A. balesae in an uncatalogued lot (RMNH) from Malmok, Aruba, collected on the same date as

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