Simpsonichthys de Carvalho,

Wilson J. E. M. Costa & Gilberto C. Brasil, 2006, Three new species of the seasonal killifish genus Simpsonichthys, subgenus Hypsolebias (Teleostei: Cyprinodontiformes: Rivulidae) from the rio Paracatu drainage, rio São Francisco basin, Brazi, Zootaxa 1244, pp. 41-55: 53

publication ID

z01244p041

publication LSID

lsid:zoobank.org:pub:21A62C97-8BE0-4382-BE2F-D1B605AA6F19

persistent identifier

http://treatment.plazi.org/id/AEFA18B6-86F1-EFB9-D896-43E59AFD00C6

treatment provided by

Thomas

scientific name

Simpsonichthys de Carvalho
status

 

[[ Simpsonichthys de Carvalho  ZBK  ]]

Discussion

In the most recent phylogenetic study (Costa, 2006), Simpsonichthys  ZBK  was divided into five subgenera: Xenurolebias Costa  , Ophthalmolebias Costa  , Simpsonichthys de Carvalho  , Spectrolebias Costa & Nielsen  , and Hypsolebias Costa  . Hypsolebias  is the most speciose clade of Simpsonichthys  ZBK  , including 24 species divided into four main clades: the S. magnificus species group  , the S. notatus species group  , the S. flammeus species group  , and the S. antenori species group  (Costa, 2006).

Simpsonichthys virgulatus  possesses the frontal squamation A-patterned (Fig. 8) and a row of small bright blue spots on the distal margin of the dorsal fin in males, which are synapomorphic features for the S. notatus species group  (Costa, 2006). This clade includes S. notatus (Costa, Lacerda & Brasil, 1990)  , S. radiosus Costa & Brasil, 2004  ZBK  ; S. similis Costa & Hellner, 1999  ZBK  ; S. trilineatus  , S. auratus  ZBK  , S. stellatus (Costa & Brasil, 1994)  , S. rufus Costa & Nielsen, 2001  ZBK  ; and S. nielseni Costa, 2005  ZBK  . Among them, S. virgulatus  shares, along with S. trilineatus  and S. auratus  ZBK  , the presence of flanks bright golden, with rows of black round blotches in males (Costa, 2006). However, another derived feature described by Costa (2006) for the clade including S. trilineatus  and S. auratus  ZBK  (i. e., brownish red pigmentation on the pectoral fin in males), is not present in S. virgulatus  , suggesting that S. trilineatus  is more closely related to S. auratus  ZBK  than to S. virgulatus  .

Simpsonichthys fasciatus  is a miniature species, only reaching a maximum adult size of about 20 mm SL. Individuals maintained in aquaria by the second author did not exceed this size after 10 months. This species is a member of the clade defined by Costa (2006) as the S. flammeus species group  , diagnosed by having spatula-shaped anal fin in females. This clade includes S. flammeus (Costa, 1989)  ; S. brunoi Costa, 2003  ZBK  ; S. multiradiatus (Costa & Brasil, 1994)  , S. alternatus  and S. delucai  ZBK  . Among them, S. fasciatus  is closely related to the clade including S. alternatus  and S. delucai  ZBK  , which is diagnosed by the rounded anal fin in males and oblique bars on the dorsal fin in males.

Simpsonichthys gibberatus  may be considered a member of the S. notatus species group  , since it shares the apomorphic A-patterned frontal squamation with species of this assemblage. This supposed phylogenetic position is reinforced by the presence of a black spot on the anterocentral portion of the flank in some males, a condition also occurring in several species of the S. notatus group  (i. e., S. notatus  , S. radiosus  ZBK  , S. similis  ZBK  , S. trilineatus  , S. auratus  ZBK  , and S. virgulatus  ). However, some incongruence to this hypothesis in noted by the absence of a row of small bright blue spots on the distal margin of the dorsal fin in males, a synapomorphy of the S. notatus group  (Costa, 2006), and the possession of gray bars on the flank in females, a condition considered plesiomorphic for Simpsonichthys  ZBK  and not occurring in other members of the S. notatus group  (Costa, 2006).