Abstract
Synbranchus lampreia, new species, is described from rio Goiapi, Marajó Island, Pará, northern Brazil. It differs from the other two described species of the genus by its color pattern, which consists of large roundish black blotches scattered over a light brown or yellowish ground pigmentation and presence of inconspicuous brown small spots distributed among the large dark spots. The species is further distinguished from S. marmoratus by a higher number of vertebrae and from S. madeira by a shorter postanal length.
Diagnosis
Synbranchus lampreia can be easily distinguished from S. marmoratus and S. madeirae by its color pattern which consists of conspicuous large black or dark brown, roundish blotches scattered along body, rare on head, and a relatively lighter ground coloration with small and inconspicuous light brown spots (Fig. 2a) (vs. more homogeneously distributed spots and marbled pattern in S. marmoratus (Fig. 2b) and gray uniform coloration with lighter roundish spots in S. madeirae).
The new species can be further distinguished from S. marmoratus by its higher number of vertebrae (161-174 vs. 116-150) and higher number of caudal vertebrae (68-76 vs. 40-63). Furthermore, the upper lip and the nuchal hump in S. lampreia is apparently less developed than in S. marmoratus. Synbranchus lampreia can be further distinguished from S. madeirae by its shorter post-anal length (23.2-28.7% vs. 34.7-37.3%).
Description
Total length of examined adult specimens 704.0 to 1167.0 mm. Like that of other synbranchids, the body is slender and nearly straight on its dorsal and ventral margins for most of its length (Fig. 1). Greatest body depth representing 5.3-5.7 % of total length. Body relatively long, with 161 to 174 vertebrae, of which 68 to 76 are caudal, in four specimens counted. Post-anal region compressed and relatively short. Pectoral and pelvic fins absent, the former present in larvae. Anal and dorsal-fin folds vestigial; dorsal-fin fold absent on anterior third of body, extremely narrow through most of its extension and more developed on portion situated posterior to the level of anus; anal-fin fold restricted to ventral midline posterior to anus. Caudal fin absent, without rays or hypurals. Scales absent.
Head conical, rounded anteriorly. Anterodorsal profile of head slightly concave to nearly straight; relatively pointed in lateral view. Snout short. Nuchal hump moderately developed. Eyes present, well developed, visible through a translucent layer of skin, and vertically aligned to posterior nostrils. Anterior nostrils on snout tip, anteriorly positioned; posterior nostrils situated medial to eyes. Mouth opening straight. Upper and lower jaws equal in forward extension. Premaxilla with a single series of small conical teeth. Two series of teeth on dentary and ectopterygoid similar in shape but somewhat larger and stronger than premaxillary teeth. Skin fold present over premaxilla and maxilla, forming a distinct upper lip.
Lateral line absent. Three pores of laterosensory system on dentary, two on preopercle, none on posttemporal or on parietal bones."
Distribution: Pará, Brazil. Habitat: freshwater.
Neotrop. ichthyol. vol.3 no.3 Porto Alegre July/Sept. 2005
http://dx.doi.org/10.1590/S1679-62252005000300001
A new Synbranchus (Teleostei: Synbranchiformes: Synbranchidae) from ilha de Marajó, Pará, Brazil, with notes on its reproductive biology and larval development
Sandra E. FavoritoI; Angela M. ZanataII; Maria I. AssumpçãoIII
