Parioglossus Regan

Rui Wang & Richard Winterbottom, 2006, Osteology and phylogeny of Parioglossus (Teleostei, Gobioidei), with a revised key to the species., Zootaxa 1131, pp. 1-32 : 1-3

[[ Genus Parioglossus Regan ]]

The gobioid fish genus Parioglossus (Teleostei: Gobioidei) was erected by Regan (1912) for the type species P. taeniatus , and now has 17 recognized described species. Most of these species inhabit warm temperate to tropical regions of the western Pacific and Indian Oceans; they are normally found around the roots of mangroves, or around algae in estuaries and coastal coral reefs. The general gestalt of members of the genus is exemplified by P. raoi (Fig. 1). Only a few of the species appear to be geographically widespread (Rennis and Hoese, 1985), and one species seems to be confined to fresh water ( P. neocaledonicus , Dingerkus and Séret, 1992).

Tomiyama (1958, 1959) reviewed the genus and recognized four valid species ( P. taeniatus Regan 1912, P. rainfordi , McCulloch, 1921, P. borneensis Koumans, 1953 and P. dotui Tomiyama, 1958). Rennis and Hoese (1985) revisited the genus, recognized 14 valid species (including six new species, and one undescribed as “P. sp”) and provided a key to the species. Since then, four additional new species have been described. Parioglossus neocaledonicus was described by Dingerkus and Séret, 1992; P. sinensis by Zhong, 1994, and the “P. sp” of Rennis and Hoese was described as P. interruptus by Suzuki and Senou (1994) who, somewhat confusingly, included another but different “P. sp” in that paper, characterized by the possession of three (instead of four) pelvic fin rays. This latter species is not included in our analysis. Finally, Williams and Lecchini (2004) described P. galzini from Rapa.

Parioglossus belongs to the family Ptereleotridae Bleeker, 1876. Although there has been some controversy as to whether to recognize this higher taxon as a family or a subfamily (see, e.g. Thacker, 2000), that issue is essentially irrelevant to this study. Miller (1971) suggested that Parioglossus shows affinity with Ptereleotris Gill 1863, Oxymetopon Bleeker 1856, Ioglossus Bean in Jordan and Gilbert 1882, and Nemateleotris Fowler 1938, with the closest relative being Ptereleotris . Iogloglossus was later relegated to the synonymy of Pterleotris by Randall and Hoese (1985). Rennis and Hoese (1987), in their description of the new pterleotrine genus Aioliops , provided a phylogenetic hypothesis for the genera they included in this subfamily. They concluded that their new genus formed an unresolved basal trichotomy with Nemateleotris on one hand, and a monophyletic grouping of Oxymetopon , Pterleotris and Parioglossus on the other. Within this latter assemblage, their osteological evidence supported the last two genera (each demonstrated to be monophyletic) as the sister group of Oxymetopon . That scheme of relationships is accepted here, and Nemateleotris (1 species) and Ptereleotris (2 species) were selected as sequential outgroups for this study. From these potential candidates, three species were used: Nemateleotris magnifica , Ptereleotris hanae and Ptereleotris microlepis .

To date, no hypothesis of the phylogeny for the species of Parioglossus has been proposed. The members of the genus are very similar in meristic and morphometric values. Some of the features, such as the number of head pores, differ dramatically between individuals within certain species. One of the most important key characters used to distinguish between the species is body coloration. It has been suggested that osteological characters of gobioid fishes may be useful in classification (Regan, 1911), as these characters tend to be more stable than external morphology and coloration. The main thrust of this paper is the comparison of both the external morphology and the osteology of the species of Parioglossus to derive a hypothesis of their interrelationships.