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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LYONS: CARIBBEAN ACANTHOCHITONIDAE 97
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Figs. 73-78. Acanthochitona venezuelana Lyons, sp. nov. Fig. 73. Valve i ex 19.0 mm paratype; Margarita Id., Venezuela; FSBC I 32569. Fig. 74. Valve iv, same specimen. Fig. 75. Valve v, same specimen. Fig. 76. Valve viii, same specimen. Fig. 77. Valve viii, 18.0 mm paratype; same lot; lateral view. Fig. 78. Tegmental pustules, valve iv, same specimen (field width = 315 /xm). more rounded, subspatulate near outer margins (Fig. 78); macresthete subcentral, 5-8 micresthetes of nearly same diameter as macresthete clustered mostly on adapical half of pustule surface. Girdle upper surface obviously spiculose, densely covered with straight to slightly curved, sharp-tipped, clear, glassy spicules (Figs. 79, 80), round in cross-section, about 300-600 /iim long, overlying and generally obscuring mat of tiny (75 f*m) slender spicules. Dorsal spicules gradually in- creasing in length to merge with marginal fringe, where they are longest (about 1 mm); no demarcation or change in form between dorsal and marginal spicules; 18 anterior and dor- sal tufts with about 25 pale green, slender, straight, sharp- pointed spicules up to 1.5 mm long; lower surface covered with small (100 /xm), densely packed, straight, slender spicules directed toward periphery. DISCUSSION: Acanthochitona venezuelana most resembles A. avicula (Carpenter, 1864). Watters (1981) noted the relation- ship between the western Atlantic A. pygmaea (as A. spiculosa) and the eastern Pacific A. avicula. Like A. pygmaea, A. avicula has broad intermediate valves (Fig. 81), longitudinal incisions on the jugum, and drop-shaped pustules. A. venezuelana has broad valves with drop-shaped to spatulate pustules but lacks jugal incisions. Most notably, dorsal girdle spicules of A. avicula and A. venezuelana virtually are iden- tical. The combination of high, pointed mucro, more narrow anterior end of the jugum, and possession of mostly ovate to subspatulate tegmental pustules separate A. venezuelana from A. avicula.

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