International Joumalfor Parasifology, Vol. 25, No. 10, pp. 1159-I 162, 1995 Copyright 0 1995 Australian Society for Parasitology Ekvier Science Ltd Pergamon 0020-7519(95)00032-l Printed in Great Britain. All rights reserved OQ2&7519/95 $9.50 + 0.00 Coomera: A New Genus of Fellodistomidae (Digenea) from 2MonodactyZrcs argenteus (Monodactylidae) of Southern Queensland, Australia A. D. M. DOVE* and T. H. CRIBB Department of Parasitology, The University of Queensland, Brisbane, Queensland 4072, Australia (Received 14 October 1994; accepted 12 April 1995) Abstract-Dove A. D. M. & Cribb T. H. Coomera: A new genus of Fellodistomidae (Digenea) from Monodactylus argenteus (Monodactylidae) of southern Queensland. International Journal for Parasitology 25: 1159-1162. A new genus, Coomera, is erected to accommodate C. hyi new species, here described from the intestine and rectum of Monodactylus urgenteus from southern Queensland, Australia. The species is character&l by a single gut caecum, conical pharynx, oblique testes, pars prostatica lined with anucleate vesicles, a large genital atrium, and a large muscular cirrus. Despite the single caecum, C. brayi is not assigned to the Monascinae for the following reasons: the sub-terminal oral sucker opens in a round aperture rather than a medial slit, the ventral sucker is larger than the oral sucker, a pre-pharynx is present, the pharynx is conical rather than elongate and the testes are symmetrical rather than tandem. These character states are shared with the Fellodistominae to which we assign this genus, suggesting that possession of a single caecum is homoplasious within the Fellodistomidae. Key words: Digenea; Australia; Coomeru brayi; Monodactylus argenteus; Fellodistomidae; Fellodistomi- nae; Monascinae. INTRODUCTION Fellodistomid digeneans collected from the intestine and rectum of the butter bream, Monodactylus argenteus (Monodactylidae), from 2 sites in southern Queensland initially appeared to be similar to members of the genus Monascus Looss, 1907 (Fel- lodistomidae: Monascinae) in having only one gut caecum. However, differences exist which prevent inclusion in that genus. A resemblance was also seen to Cercariu praecox (Walker, 1971), but again the specimens did not agree. Despite having only one gut caecum, the present material shares many similarities with members of the Fellodistominae, particularly the genus Steringophorus. As the present specimens *To whom all correspondence should be addressed. do not, however, agree with any existing genus of Fellodistomidae, the new genus Coomera is proposed to accommodate them. MATERIALS AND METHODS Specimens of Monodactylus argenteus were collected by line fishing; 7 of 8 from Hope Island, Moreton Bay (27”25’S, 153”2O’E) and 5 of IO from North Stradbroke Island (27”24’S, 153”26’E) were infected with the new trematode. Worms were dissected from the intestine of infected fish and 6xed in near-boiling 5% forrnalin. Speci- mens were stained in Mayer’s haematoxylin before dehy- dration through an alcohol series, clearing in methyl salicylate and mounting in Canada balsam. Two specimens were sectioned in the sagittal plane at 7 pm and stained with Mayer’s haematoxylin and eosin before mounting in Depex mounting medium. Dimensions were measured using an II59