Sicyopterus, Gill, 1860

SPARKS, JOHN S. & NELSON, DOUGLAS W., 2004, Review of the Malagasy Sicydiine Gobies (Teleostei: Gobiidae), with Description of a New Species and Comments on the Taxonomic Status of Gobius lagocephalus Pallas, 1770, American Museum Novitates 3440 (1), pp. 1-20 : 1-2

Freshwater gobies of the genus Sicyopterus Gill, 1860 (subfamily Sicydiinae ) inhabit tropical and subtropical swift­flowing streams and rivers in the Indo­Pacific region, islands of the southwestern Pacific Ocean, and islands of the Mascarene region in the

1 Department of Ichthyology, Division of Vertebrate Zoology, American Museum of Natural History; reprint requests to [e-mail]

2 Division of Fishes, Museum of Zoology, University of Michigan, Ann Arbor, Michigan 48109; e­mail: dwnelson@ umich.edu

Copyright © American Museum of Natural History 2004

ISSN 0003­0082

western Indian Ocean. These small fishes are often referred to as ‘‘rock­climbing gobies’’ due to their ability to ascend steep, torrential streams and waterfalls ( Fukui, 1979; Parenti and Maciolek, 1993; Balon and Bruton, 1994). Throughout their range, sicydiine gobies exhibit a high degree of island­group endemism ( Parenti and Maciolek, 1993, 1996; this study). Two species of Sicyopterus are presently known to inhabit the freshwaters of Madagascar ( Sparks and Stiassny, 2003): One of these is herein described as new to science.

Monophyly of sicydiine gobies is well supported by morphological evidence ( Hoese, 1984; Harrison, 1989; Parenti and Maciolek, 1993; Birdsong et al., 1998; Parenti and Thomas, 1998). Parenti and Maciolek (1993) and Parenti and Thomas (1998) recognized five genera within the subfamily Sicydiinae : Sicydium Valenciennes , in Cuvier and Valenciennes, 1837, Sicyopterus Gill, 1860 , Lentipes Günther, 1861 , Sicyopus Gill, 1863 , and Stiphodon Weber, 1895 . On the basis of a low number of premaxillary teeth (7– 23 vs.> 25 in other Sicydiinae ), Watson (1995a) recognized a sixth sicydiine genus from Réunion and Mauritius, Cotylopus Guichenot, 1863 . The subfamily comprises about 100 nominal species; approximately 40 of these species are presently placed in the genus Sicyopterus ( Parenti and Maciolek, 1996; Eschmeyer, 1998). Sicyopterus and Sicydium are hypothesized to be sister genera based on the following derived features: an uninterrupted oculoscapular canal extending posteriorly from the eye to the posterior margin of the opercle, with fusion of oculoscapular­canal pores H and K (Akihito et al., 1984; Pezold, 1993), and a blunt ascending process of the premaxilla ( Parenti and Maciolek, 1993). Akihito and Meguro (1979) presented and discussed a number of features useful for distinguishing between members of Sicydium and Sicyopterus . Sicyopterus has been hypothesized to be monophyletic on the basis of a marked medial gap between the left and right premaxillary tooth rows ( Parenti and Maciolek, 1993, 1996).

In this paper we review the species of sicydiine gobies inhabiting Madagascar and the Mascarene region, describe a new species of Sicyopterus from northeastern Madagascar (fig. 1), and compare the new taxon with S. franouxi ( Pellegrin, 1935) , the only other sicydiine goby known to inhabit the freshwaters of Madagascar. Pellegrin described S. franouxi on the basis of a single juvenile specimen. Herein, we redescribe this taxon on the basis of adult material. We also discuss the taxonomy of Gobius lagocephalus Pallas, 1770 , a nominal sicydiine taxon historically and incorrectly ascribed to Madagascar and other islands of the Mascarene region. A summary of the taxonomic conclusions of this study is presented in table 1.