Plesiolebias Costa

Wilson J. E. M. Costa, 2007, Taxonomy of the plesiolebiasine killifish genera Pituna, Plesiolebias and Maratecoara (Teleostei: Cyprinodontiformes: Rivulidae), with descriptions of nine new species., Zootaxa 1410, pp. 1-41 : 20-21

Plesiolebias Costa

Plesiolebias Costa, 1989b : 193 (type species: Cynolebias xavantei Costa, Lacerda & Tanizaki , by original designation).

Diagnosis. Distinguished from all other genera of Plesiolebiasini by the following unique features: posterior process of quadrate and sympletic long (vs. short) (Costa, 1998a), interarcual cartilage absent (vs. present) (Costa, 1998a), rays of anterior portion of anal fin longer than posterior rays (vs. longer) (Costa, 1995a), and frontal squamation G-patterned (vs. F or D patterned) (Costa, 1998a).

Distribution. Southeastern Amazonian basin, including Xingu, Araguaia, and Tocantins river drainages, Brazil; and rio Paraguay basin, in northern Brazilian Pantanal (Fig. 13).

Remarks. The systematic accounts below should be viewed as a complement to the recent taxonomic revision of Plesiolebias (Costa, 1998c), where redescriptions of P. xavantei , P. lacerdai , P. aruana , and P. glaucopterus are included.

Key to species of the genus Plesiolebias

1a. Pelvic-fin rays 8-9; pelvic-fins each with a long filamentous ray in males; eye yellow in males; anterior portion of flank, at least, with oblique black bars in males; red stripe of anterior portion of flanks, when present, never anteriorly reaching orbit; basal portion of dorsal fin red in males; a black spot on posterior portion of anal fin in males, most prominent in preserved specimens..................................2

1 b. Pelvic-fin rays 7; pelvic-fins each without filamentous rays; eye bright green in males; never oblique black bars on flanks in males; red stripe of anterior portion of flanks always anteriorly reaching orbit; basal portion of dorsal fin with transverse rows of dark red and white spots in males; never a black spot on posterior portion of anal fin in males ..................................................................................................... 6

2a(1a). Body depth 23.2-25.7 % SL in males, 23.0-26.0 % SL in females; sparse bright dots on flank in males; 3 white bars on basal portion of anal fin in males ...................................................................... 3

2b(1a). Body depth 28.6-32.6 % SL in males, 26.4-30.3 % SL in females; oblique rows of bright dots on flanks of males; 4-5 white bars on basal portion of anal fin in males ................................................... 4

3a(2a). No red mark on anterior portion of flanks in males; no black bar on preopercle; 5-7 oblique bars on flanks in females; 24-25 scales in longitudinal series ......................................... P. fragilis , new species

3b(2a). A red stripe on anterior portion of flanks in males; a black bar on preopercle; 8-9 oblique bars on flank in females; 22-23 scales in longitudinal series ...................... P. altamira Costa & Nielsen , new species

4a(2b). Dorsal-fin origin on vertical between base of 3rd and 5th anal-fin rays; no red mark on anterodorsal portion of head in males ..................................................................................................... P. lacerdai Costa

4b(2b). Dorsal fin-origin on vertical between base of 5th and 8th anal-fin rays; red stripe on anterodorsal portion of head in males .............................................................................................................................. 5

5a(4b). Dorsal fin-origin at vertical between base of 5th and 6th anal-fin rays; 15-16 anal-fin rays; red pigmentation restricted to basal third of dorsal fin in males; small white spots on dorsal-fin base in males ..... ........................................................................................... P. filamentosus Costa & Brasil , new species

5b(4b). Dorsal fin-origin on vertical between base of 7th and 8th anal-fin rays; 17-18 anal-fin rays; red pigmentation extending to basal two thirds of dorsal fin in males; white bars on dorsal-fin base in males ....... ................................................................................................. P. xavantei (Costa, Lacerda & Tanizaki)

6a(1b). Dorsal-fin origin on vertical between base of 7th and 9th anal-fin rays; oblique rows of dark brown dots restricted to the median portion of flank, sometimes absent ................................................................. 7

6b(1b). Dorsal-fin origin on vertical through base of 5th or 6th anal-fin ray; dark brown dots and elongated spots on whole flank in females ........................................................ P. glaucopterus (Costa & Lacerda)

7a(6a). Anal-fin base with white elongate spots in males; 1 + 27-31 + 1 infraorbital neuromasts ..................... ...................................................................................... P. canabravensis Costa & Nielsen , new species

7b(6a). Anal-fin base with long curved bars in males, ventral tips anteriorly directed, often converging to a point on anterior margin of fin; 1 + 16-22 + 1 infraorbital neuromasts .................... P. aruana (Lazara)