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Description of two new miniature species of Hylopanchax Poll & Lambert, 1965 (Cyprinodontiformes: Procatopodidae), from northeastern Gabon, with an updated diagnosis of the genus based on morphology, colouration and osteology
Author(s) -
Bragança Pedro H. N.,
Zee Jouke R.,
Sonnenberg Rainer,
Vreven Emmanuel J. W. M. N.
Publication year - 2021
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/jfb.14606
Subject(s) - osteology , biology , anatomy , genus , reticulate , zoology , paleontology
Two new species of the lampeye genus Hylopanchax are described from the Ivindo River basin in the Ogowe River drainage. Hylopanchax multisquamatus , new species, and Hylopanchax thysi , new species, differ from congeners by the presence of a hyaline urogenital male papilla with small black spots and a dark‐brown reticulate pattern on the flanks of both males and females in preserved specimens. Hylopanchax multisquamatus is distinguished from congeners by the number of scales on the mid‐longitudinal series (27–30 vs . 19–26, respectively) and by the relative anterior/posterior flank scale depth ratio (140%–150% vs . 170%–220%). Hylopanchax thysi is distinguished from all other congeners, except Hylopanchax paucisquamatus , by the presence of vertebrae (30 vs . 31–33) and is further distinguished from H. multisquamatus by the presence of a deeper caudal peduncle and much larger anterior flank scales. It is distinguished from H. paucisquamatus by the presence of a hyaline urogenital male papilla with small black spots and a dark‐brown reticulate pattern on the flanks of both males and females in preserved specimens. Osteological data of Hylopanchax are presented for the first time, and an updated diagnosis based on external morphology, colouration pattern and osteology is provided. An osteological comparison with closely related species belonging to the genera Procatopus , Hypsopanchax and “ Hypsopanchax ” is presented. (a) A truncate and slightly downward‐directed anterior process of the angulo‐articular and (b) a guitar‐shaped lachrymal with both its anterior and posterior margins sharply curved are here considered as diagnostic features of Hylopanchax .