Priocharax britzi Mattox, Souza, Toledo-Piza & Oliveira, 2021

Family:  Characidae (Characins; tetras), subfamily: Characinae
Max. size:  1.41 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; depth range 0 - 1 m
Distribution:  South America: Brazil.
Diagnosis:  Dorsal soft rays (total): 9-9; Anal soft rays: 22-27; Vertebrae: 32-33. This species is distinguished from all its congeners except P. pygmaeus by having lower number of teeth in the maxilla 21-30 (vs 32-58) and dentary 26-29 (vs 33-55); differs from P. pygmaeus by the presence of two postcleithra (vs. absence and branched anal-fin rays 22-27 modes 25 and 26 (vs. 19-22, mode 19); differs fom P. nanus and P. varii by having pelvic-fin rays i,5 (vs.i,6) and postcleithrum 3, slender and sinuous (vs. relatively thick and straight); differs from P. ariel by the branched anal-fin rays 22-27 (vs. 16-22) and with two postcleithra (vs. absent); further differs from P. varii by the absence of the adipose fin (vs. presence) and from P. nanus by the absence of the claustrum (vs. presence); with a shorter snout relative to the orbital diameter when compared to all congeners except P. nanus [range of the proportion of snout length in relation to orbital diameter and its mean is 45-59 (mean = 53.6; SD = 3.8) in P. britzi vs. 60-76 (mean = 65.5; SD = 4.9) in P. pygmaeus, 54-81 (mean = 67.0; SD = 5.1) in P. varii and 54-84 (mean = 68.4; SD = 6.3) in P. ariel]. Molecular analyses further support the recognition of the new species (Ref. 124594).
Biology:  Specimens were collected from a small lake approximately 15 m wide and 35 m long, apparently isolated from the main channel of the rio Ipixuna and where the water level was low as sampling occurred during the dry season (September). It is possible that this lake connects to the main channel in the wet season. Collection was done near the shore at depths varying from 0.5–1.0 m, when the bottom was muddy with patches of leaf litter. Vegetation around the lake was composed mainly of dead logs and branches. Collected with the characiforms Carnegiella marthae, Hemigrammus sp., Hyphessobrycon rosaceus. Iguanodectes spilurus, Microcharacidium sp., Nannostomus digrammus, Nannostomus eques; the catfish Amblydoras affinis; the knifefishes Brachyhypopomus beebei, Microsternarchus bilineatus; the cichlids Apistogramma cf. pulchra, Biotoecus opercularis and Crenicichla cyanotus (Ref. 124594).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless


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