Tegastes falcatus (Norman, 1868) and T. nanus Sars, 1904, are reported for the first time from the east coast of the United States. Both occurred on the red alga Ptilota serrata, and T. nanus also on the kelp Laminaria digitata. Tegastes nanus is redescribed. Known living substrates of the genus Tegastes Norman, 1903, are briefly discussed. Members of the harpacticoid copepod genus Tegastes are infrequently encountered, and relatively little is known about them. The small size (< 0.5 mm) of species of Tegastes, combined with their occurrence on substrates that are not often sampled in meiofaunal surveys, has apparently limited information about the genus. Species of Tegastes have been reported as associates of cnidarians (Humes, 1984) and bryozoans (Medioni and Soyer, 1967), and Hicks and Coull (1983) regarded them as typical members of phytal meiofaunal assemblages. We note here the first records from the east coast of the United States of T. falcatus (Norman, 1868) and T. nanus Sars, 1904. We redescribe the latter because both the original description by Sars (1904) and the comments of Chislenko (1967) are very brief, especially with respect to the male. One male of T. nanus was recovered from a plankton tow. The other animals discussed here came from algal specimens which were collected in the manner noted by Gerlach (1971). Divers covered the algae with small, plastic bags, then scraped the plants from the bottom and sealed the bags. Bags were returned to the tending vessel and the specimens were transferred to 6% MgCl2 for 10-min anesthetization, after which buffered Formalin was added to make a 4% concentration. In the laboratory, copepods and other meiofauna were recovered by shaking the sample jars, and then filtering their contents through 1.0-mm and 0.063mm screens. Copepods recovered from algal washings and from the plankton were kept in 4% Formalin, and later put into 85% lactic acid for examination. Drawings were made with the help of a camera lucida. Tegast s nanus Sars, 1904 Material Examined. -1 8, from plankton tow, Damariscotta River, Maine (43'56'N, 69'35'W), May 1981; 4 99, 2 $, from fronds ofPtilota serrata collected by diving at 20 m, October 1981; several 99 from holdfasts of Laminaria digitata collected by diving at 14 m, February 1982; last two collections off the coast of New Hampshire (42054'N, 70047'W). Male. -Length 0.32 mm. Body laterally compressed, roughly void in lateral view, strongly curved dorsally (Fig. 1). Cephalosome large, mu h produced downward on each id to narrowly rounded terminus. Cephalosome separated from metasome by distinct, sclerotized st ipe. Abdomen faintly rugose, genital somite expanded into massive spermatopho e reservoir having small ventral and post rior projections (Fig. 2). Remainder of urosome small; caudal rami very small, each bearing 2 dorsal and 3 subequal terminal setae (Fig. 2). Color pale, golden brown, darkening to chestnut along sutures between somites. First antenna 8-segmented, flexure between segments 5 and 6; aesthetasc on segment 5 (Fig. 3). Second antenna with no seta on basis; exopod minute, 2-segmented, bearing 2 terminal setae; endopod 2-segmented, first segment with 1 anterior seta, second with 2 anterior and 3 terminal setae (Fig. 4). Mandible with 4 smooth teeth and 1 seta on precoxa, 3 terminal setae on endopod (Fig. 8). First maxilla with 4 very small, smooth teeth on precoxa; coxa bearing single seta; basipod with 3 long, 1 short, terminal setae (Fig. 9). Second maxilla having 2 closely spaced, distal, coxal endites, outer bearing 3 stout, barbed setae, inner a smooth seta; basis with 4 setae, terminal 2 stronger than others (Fig. 10). Maxilliped
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Jan 1, 2012
David A Nickle + 1
Open Access
