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[[ Subfamily Loricariinae ]]
Members of the subfamily Loricariinae are characterized by a long and depressed caudal peduncle and by the absence of an adipose fin. They also show dramatic variation in body shape, lip morphology and dentition. The sexual dimorphism is often pronounced and is expressed through the hypertrophy of odontodes on the pectoral-fin rays, on the snout margin, and sometimes on the predorsal area of mature males. Certain genera also show sexual differences in lip and tooth structures.
Isbrücker (1979) listed twenty-seven genera of Loricariinae , described eight as new, and classified them into four tribes and eight subtribes on the basis of morphology, without phylogenetic inferences. These include the Loricariini , including six subtribes ( Loricariina , Planiloricariina , Reganellina , Rineloricariina , Loricariichthyina and Hemiodontichthyina ), the Harttiini , including two subtribes ( Harttiina and Metaloricariina ), the Farlowellini , and the Acestridiini . The same author (1981a: p. VI, 71) voiced doubts concerning the placement of Acestridiini among Loricariinae , noting that: “The exposed cleithrum and coracoid, together with the peculiar odontodes on the unbranched pelvic fin ray (‘spine‘) are characters otherwise occurring typically only in various members of the subfamily Hypoptopomatinae .”; nevertheless, he maintained them as members of Loricariinae . In the same work he also described two new subtribes, Ricolina and Pseudoloricariina , developed the main characteristics of each rank: subfamily, tribe, subtribe, and genera, and provided a provisional key to the genera of Loricariidae . Rapp Py-Daniel (1981) described a new genus, Furcodontichthys ZBK , and placed it in the Loricariini , subtribe Loricariina . Martín Salazar et al. (1982) described Dentectus ZBK as a representative of the tribe Loricariini , subtribe Planiloricariina . In this paper, he completed the diagnosis of Planiloricariina , in which he transferred the genera Rhadinoloricaria ZBK , Crossoloricaria ZBK , and Pseudohemiodon ZBK . Isbrücker et al. (1983) described Aposturisoma ZBK as a representative of the Farlowellini . Isbrücker & Nijssen (1984, 1986a) described Pyxiloricaria ZBK and Apistoloricaria ZBK , respectively, and placed them in the Loricariini , subtribe Planiloricariina . Using phylogenetic methods, Schaefer (1986, 1987) established the monophyly of the Loricariinae on the basis of morphological data. Finally, Nijssen & Isbrücker (1987) suggested, refering to a Ferraris personal communication, that the Acestridiini were representatives of the subfamily Hypoptopomatinae . Schaefer (1991) confirmed this status and diagnosed the tribe Hypoptopomatini including, among others, the Acestridiini . Rapp Py-Daniel (1997) proposed a phylogeny of the Loricariinae based on a phylogenetic analysis of morphological characters. She confirmed the monophyly of the subfamily, and of two of the three remaining tribes sensu Isbrücker (1979), Harttiini and Loricariini ; members of Farlowellini were placed within Harttiini . Montoya-Burgos et al. (1998) proposed the first molecular phylogeny of the familyLoricariidae with emphasis on the subfamily Hypostominae . Although, their analysis included only nine representatives of the subfamily Loricariinae , they partially confirmed their subdivision into two main groups, with Farlowella ZBK , a representative of the Farlowellini , being the sister genus of Sturisoma , a representative of the Harttiini , and Harttia ZBK located at the base of the subfamily. Outside of Harttia ZBK , the two main groups supported were Farlowella ZBK and Sturisoma sister group of the remaining six genera corresponding to Loricariini . Isbrücker and Isbrücker & Michels (in Isbrücker et al. 2001) described four new genera: Fonchiiichthys ZBK , Leliella ZBK , Quiritixys ZBK and Proloricaria ZBK , and revalidated the genus Hemiloricaria Bleeker, 1862 ZBK on the basis of a very restricted number of characters of questionable validity because they focus mainly on sexual dimorphism. Rapp Py-Daniel & Oliveira (2001) put Cteniloricaria ZBK in the synonymy of Harttia ZBK . Ferraris (2003) maintained the validity of Cteniloricaria ZBK , put in synonymy all the genera described by Isbrücker and Isbrücker & Michels (in Isbrücker et al. 2001) and listed 197 species of Loricariinae distributed in 31 genera: Apistoloricaria ZBK (4 species), Aposturisoma ZBK (1 species), Brochiloricaria ZBK (2 species), Crossoloricaria ZBK (5 species), Cteniloricaria ZBK (3 species), Dasyloricaria ZBK (5 species), Dentectus ZBK (1 species), Farlowella ZBK (25 species), Furcodontichthys ZBK (1 species), Harttia ZBK (18 species), Harttiella ZBK (1 species), Hemiodontichthys ZBK (1 species), Ixinandria ZBK (2 species), Lamontichthys ZBK (4 species), Limatulichthys ZBK (1 species), Loricaria ZBK (11 species), Loricariichthys ZBK (17 species), Metaloricaria ZBK (2 species), Paraloricaria ZBK (3 species), Planiloricaria ZBK (1 species), Pseudohemiodon ZBK (7 species), Pseudoloricaria ZBK (1 species), Pterosturisoma ZBK (1 species), Pyxiloricaria ZBK (1 species), Reganella ZBK (1 species), Rhadinoloricaria ZBK (1 species), Ricola ZBK (1 species), Rineloricaria ZBK (47 species), Spatuloricaria ZBK (11 species), Sturisoma (14 species), and Sturisomatichthys ZBK (4 species). Among all these genera, 13 are monotypic and very few of the most speciose have been revised. Loricaria ZBK was revised by Isbrücker (1981b), Metaloricaria ZBK by Isbrücker & Nijssen (1982), Apistoloricaria ZBK by Nijssen & Isbrücker (1988), and Farlowella ZBK by Retzer & Page (1997).
In light of all these works, which are sometimes contradictory, a taxonomic synthesis of Loricariinae is needed to provide a foundation for more detailed studies of its members. Furthermore, despite the large number of studies conducted on this group, a complete key to the genera of the subfamily Loricariinae is presently unavailable; partial keys are available in Isbrücker & Nijssen (1974a; 1986b), Isbrücker (1981b), Rapp PyDaniel(1981), and Burgess (1989). To rectify this situation, a key to all the genera of the subfamily is proposed herein on the basis of external morphological data, and a synopsis is given for each genus. Multivariate and hierarchical analyses were conducted to classify and organize the information used to construct the key. Our study follows the classification of Ferraris (2003), except for maintaining Cteniloricaria ZBK in synonymy with Harttia ZBK (Rapp Py-Daniel & Oliveira 2001). As a result, we recognize herein 30 genera of Loricariinae .