Redescription of Hatschekia exigua Pearse, 1951 (Copepoda: Hatschekiidae), parasitic on the Squirrelfish Holocentrus adscensionis (Osbeck, 1765) (Actinopterygii: Holocentridae) off Ceará, Northeastern Brazil, with first description of the male
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引用次数: 0
Abstract
The original description of Hatschekia exigua Pearse, 1951 neglected innumerous features of taxonomic value as well as morphometric data and illustrations. Posteriorly, other author tried to access the type material, but their poor state of preservation compromised a detailed redescription. Since then, this species is in need for new morphological data, mainly from fresh material. In the present work, three specimens of Holocentrus adscensionis from Mucuripe Bay, Fortaleza, State of Ceará, Northeastern Brazil, were parasitized by copepods on their gills. Parasites were fixed and preserved in 80% ethanol and cleared in 85% lactic acid for morphological observations using light microscopy. The females were identified as Hatschekia exigua by the cephalothorax representing about one-fourth of total body length, with lateral margins expanded into lateral lobes, first exopod with basal segment armed with one outer setae and terminal segment with three setae, first endopod with basal segment unarmed and terminal segment with five setae, leg 3 reduced to two setae and leg 4 reduced to single seta. Comparison with the type series revealed morphological differences in trunk and small appendages, which may be related to alterations in the specimens, caused by the mounting methodology and poor preservation. A detailed morphological analysis of the male revealed for the first time that they differ from their closest congeners by having five setae on the last endopodal segment of leg 1, by smooth intercoxal sclerites on legs 1 and 2 and by a proximolateral process on the third segment of antenna. Moreover, this work represents the first report of H. exigua in Brazil and the first hatschekiid copepod found off the coast of Ceará, highlighting that the diversity of Hatschekiidae in this oceanographic region still needs further investigation.
期刊介绍:
Systematic Parasitology publishes papers on the systematics, taxonomy and nomenclature of the following groups: Nematoda (including plant-parasitic), Monogenea, Digenea, Cestoda, Acanthocephala, Aspidogastrea, Cestodaria, Arthropoda (parasitic copepods, hymenopterans, mites, ticks, etc.), Protozoa (parasitic groups), and parasitic genera in other groups, such as Mollusca, Turbelleria, etc. Systematic Parasitology publishes fully illustrated research papers, brief communications, and fully illustrated major revisions. In order to maintain high standards, all contributors describing new taxa are asked to state clearly where the holotype is deposited and to make paratypes available for examination by the referees. It is recognized that, in some cases, this may cause problems for the authors, but it is hoped that by adhering to this rule authors may be protected against rapid synonymy of their taxa, and the types will be preserved for posterity.