Comprehensive DescriptionRead full entry
Lectotype : NMW 46346 , Brazil , Rio Paraiba do Sul.
Distribution primarily includes rivers draining the Guyana Shield, coastal rivers in northeastern Brazil, and the Amazon basin. These rheophilic fishes are found in the upper courses of rivers over rocky and sandy bottoms. Casatti & Castro (2006) characterized ecomorphological trends in fishes living in riffles of the Rio São Francisco. They split the fish communities into three groups comprising nektonic, nektobenthic, and benthic species. Among the latter, Harttia ZBK sp. is supposed to be able to exploit areas with the strongest current, because of its extremely depressed body and long caudal peduncle, comparing to other species. This fact was also empirically noted by Le Bail et al. (2000). Sexual dimorphism includes hypertrophied odontodes on the pectoral spines and along the margins of the snout in mature males. Representatives of this genus seem to be open brooders (Dotzer & Weidner 2003). Recent evidence has suggested that Harttiini could represent a paraphyletic assemblage. Using molecular data, MontoyaBurgos et al. (1998) demonstrated Harttia ZBK to be sister to two sister clades, one consisting of Farlowella ZBK and Sturisoma , two representatives of the Harttiini , and the second including the representatives of the Loricariini . Moreover, Harttia ZBK is in need of revision. For example, the synonymy of Cteniloricaria ZBK with Harttia ZBK (Rapp Py-Daniel & Oliveira 2001) is questionable (Covain et al. 2006) because it rests solely on the characteristics of Harttia fowleri (Pellegrin, 1908) without considering the type species of Cteniloricaria ZBK . Likewise, the genus Quiritixys Isbruecker , 2001 ZBK , also placed in synonymy by Ferraris (2003) is possibly valid. The description of Quiritixys ZBK is based on the unusual sexual dimorphism of Harttia leiopleura Oyakawa, 1993 ZBK . This feature alone is insufficient to define a genus because it only concerns mature males and is most of the time seasonal in Loricariinae . This means that the majority of individuals of the species (juveniles, females, and non breeding males) cannot be diagnosed by this single criterion because they do not possess this feature. Nevertheless, the addition of some other features by Oyakawa (1993), such as the absence of the subpreopercle, supports the validity of Quiritixys ZBK . Other species such as H. novalimensis ZBK could also belong to Quiritixys ZBK because this species also lacks the subpreopercle, but its sexual dimorphism is undescribed. Nevertheless, Langeani et al. (2001) noted well developed odontodes on the posterior body of this species. Harttia ZBK also exhibits considerable karyotypic diversity with chromosome numbers between 2n = 52 and 2n = 58 in the four species characterized (Kavalco et al. 2005, Centofante et al. 2006). Kavalco et al. (2005) also reported differences in karyotypic formula, symmetry, nucleolar organizing regions (NOR), and diploid number (2n = 52 versus 2n = 56) between two different populations (respectively Grande Stream and Paraitinga River) of H. loricariformis ZBK from the Paraíba do Sul basin. These authors hypothesized the sedentary habits of some species to explain these differences. Centofante et al. (2006) characterized a heteromorphic XX/XY1Y2 sex chromosome system in H. carvalhoi ZBK . Currently, Harttia ZBK comprises 22 species (Provenzano et al. 2005). Partial keys are available for species occurring in Atlantic coastal drainages (Oyakawa 1993, Langeani et al. 2001), Amazon and Guianas drainages (Rapp Py-Daniel & Oliveira 2001), and Guianas drainages (Covain et al. 2006).