Eleotrica, GINSBURG, 1933

Tornabene, Luke, Van Tassell, James L., Gilmore, Richard G., Robertson, David Ross, Young, Forrest & Baldwin, Carole C., 2016, Molecular phylogeny, analysis of character evolution, and submersible collections enable a new classification of a diverse group of gobies (Teleostei: Gobiidae: Nes subgroup), including nine new species and four new genera, Zoological Journal of the Linnean Society 177 (4), pp. 764-812 : 778

ELEOTRICA GINSBURG, 1933

TYPE SPECIES: ELEOTRICA CABLEAE GINSBURG, 1933 (P. 10, by Original Designation)

Diagnosis

Possesses all taxonomic characters present in most members of Gobiosomatini and Gobiosoma group (first dorsal-fin spines VII, pterygiophore insertion pattern of 3 – 221110, 27 vertebrae – 11 precaudal and 16 caudal, hypurals 1 and 2 fused to some extent with hypurals 3 and 4 and the terminal vertebral element, one epural); pelvic fins well separated, lacking both anterior frenum and welldeveloped membrane connecting innermost rays; pelvic-fin rays 1 – 4 branched and never with flattened or fleshy tips, fifth pelvic-fin ray sometimes branched once near tip; pelvic-fin rays extending posteriorly to anus, never reaching origin of anterior anal-fin rays; side of body without scales (modified basicaudal scales present); two anal-fin pterygiophores inserted before first haemal spine; papillae rows 5i and 5s separate; cephalic sensory canals present, pores B 0, D, F, and H 0 present on raised short tubes; second dorsal-fin rays I,11; anal-fin rays I,9 – 10; body variously mottled with numerous small white spots on head and body, background colours generally with light tones that match the substrate from which it was collected, sometimes with a series of horizontally paired small dark spots along lateral midline. The one known species occurs in the eastern Pacific Ocean from the Galapagos Islands.

Remarks

The single species in this genus, Eleotrica cableae , is known only from the Galapagos Islands. It is generally a shallow water species that occurs from tide pools to depths of around 21 m, although a single record exists from a depth of 48 m off Santa Cruz ( CAS 54523), which we have not examined. The phylogenetic placement of this species is uncertain. Eleotrica has the distinctive apomorphic feature of raised tubes at the opening of the cephalic sensory canal pores. It possesses a number of plesiomorphic characters, including two anal-fin pterygiophores, inserted before the first haemal spine, and separate papillae rows 5i and 5s. The loss of body scales and the presence of cephalic lateralis canals are characters shared with Gobulus ; however, it is uncertain whether this is a result of common ancestry or possibly convergent adaption to a similar microhabitat (both occur in shallow, exposed habitats). Besides the Pacific members of Gobulus , no other Pacific species in the Nes subgroup completely lack body scales; however, the extent of squamation is variable across Chriolepis , and many species lack scales anteriorly. We were unable to obtain tissue samples for Eleotrica for molecular analysis, and we maintain Eleotrica as a valid genus pending further phylogenetic investigation.