Peniculus haemuloni, a new species of copepod (Siphonostomatoida: Pennellidae) parasitic on Haemulon steindachneri from Ubatuba, Brazil P. D. Alexander *c/o The Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD. Introduction The genus Peniculus was established by Nordmann, 1 832, to accommodate Peniculus fistula, a parasite of the teleost fish Diplodus annularis Linnaeus (as Sargus annularis). To date 17 nominal species exist although according to Kabata (1979) at least two of them should be regarded as species inquirendae: P. calamus Nordmann, 1864 and P. fissipes Wilson, 1917, the latter probably being a synonym of the type species. The new species is the first record of Peniculus from Brazilian waters and the first record of Haemulon as a host for Peniculus. The structure of the appendages within the Pennellidae is so uniform that they are of little taxonomic value for species recognition. The key to the species of Peniculus is based on gross body morphology. Description of new species Peniculus haemuloni n.sp. Adult female: The cephalothorax is about one tenth as long as the trunk (Fig. 1A), ovoidal, and flattened dorsally but convex ventrally (Fig. IB) with a pair of rounded swellings anter-iorly bearing the second antennae (Fig. ID). The prominent mouth tube is directed postero-ventrally (Fig. 1C). The four thoracic segments form a relatively short, uniformly slender neck comprising about one sixth of the trunk length. The neck is slightly flattened dorso-ventrally and has a conspicuous internal system of longitudinal and transverse chitinous thickenings (Fig. 1C). Posteriorly the neck bears three pairs of swimming legs. The elongate subcylindrical trunk is slightly dorsoventrally flattened and comprises four-fifths of the total body length (Fig. 1 A). A pair of terminal ventrolateral swellings bears the oviduct openings. The egg sacs are straight and uniseriate (Fig. 2B). The small rounded, dorsally placed abdo-men bears two groups of four short setae (Fig. 2C) which are presumed to represent the caudal rami. The first antennae are absent. The second antennae are stout with a strongly curved terminal claw. The mouth tube is well developed extending almost to the posterior margin of the cephalothorax. The apex of the mouth tube has a circular opening surrounded by a thin membrane. The swimming legs comprise an oval flattened protopod and a 2-segmented exopod. The first segment is devoid of armature elements, the second has five setae on both the first and the third legs, the second leg armature was missing. Each limb pair is connected by a sternal bar (Fig. 2 A). Dimensions of the holotype female: total length (exc. egg sacs) 5-6 mm; trunk length 4-4 mm; trunk width, 0-6 mm; neck length, 0-7 mm; neck width, 0-1 mm; cephalothorax length, 0-5 mm; cephalothorax width, 0-35 mm; egg sac width, 0-16 mm. MATERIAL EXAMINED. Two adult females from the tail fin of the teleost Haemulon steindach-neri collected at Ubatuba, Brazil (2327 'S: 4506 'W) by Dr K. Rohde in March 1979. The *Work completed during a six month secondment from the Department of Applied Biology, U.W.I. S.T. King Edward VII Avenue, Cardiff. Bull. Br. Mus. nat. Hist. (Zool.) 45(7): 381-385 Issued 24 November 1983 381
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