Description of a new genus and three new species of Otothyrinae (Siluriformes, Loricariidae)

Abstract The genus Hisonotus was resurrected as a member of the tribe Otothyrini (actually subfamily Otothyrinae). However, phylogenetic studies based on morphological and molecular data showed that Hisonotus is not monophyletic and independent lineages can be identified, such as the group composed of the species Hisonotus insperatus, Hisonotus luteofrenatus, Hisonotus oliveirai, Hisonotus paresi and Hisonotus piracanjuba, a lineage unrelated to that containing the type species of the genus Hisonotus (Hisonotus notatus). Herein, based in molecular and morphological data, a new genus is described to accommodate the lineage mentioned above, into which are also added three new species. This new genus can be distinguished from other genera of Otothyrinae by the following combination of characters: (1) a pair of rostral plates at the tip of the snout; (2) two large pre-nasal plates just posterior to the rostral plates; (3) a supra-opercular plate that receives the laterosensory canal from the compound pterotic before the preopercle; (4) a well developed membrane at anal opening in females; and (5) a V-shaped spinelet. A key to species of Curculionichthys is provided.


Introduction
The subfamily Otothyrinae (sensu Chiachio et al. 2008 andRoxo et al. 2014a) is one of the most diverse members of Loricariidae, distributed through almost all South America, in hydrographic systems from the Amazon to northern Argentina. Within this subfamily, the genus Hisonotus Eigenmann & Eigenmann, 1889 is composed of 35 species (Eschmeyer 2015) in drainages of southern and southeastern Brazil, from the Rio Uruguay basin, upper Rio Paraná, Laguna dos Patos and Coastal drainages extending from Rio Grande do Sul State to Rio de Janeiro State and the Amazon basin. This genus was resurrected by Schaefer (1998a) with the combination of the following characters: reduced or absent snout plates in the anterior portion of the nostril, rostrum with enlarged odontodes, and thickened plates forming the lateral rostral margin. However, Britski and Garavello (2007) argued that the characters used by Schaefer (1998a) for the definition of Hisonotus, as well as other genera of the Otothyrinae, needed to be redefined. For example, Britski and Garavello (2007) observed that a rostrum with enlarged odontodes is present in several genera and species of Otothyrinae, as well as in Parotocinclus Eigenmann & Eigenmann, 1889. Furthermore, Britski and Garavello (2007) suggested that the other two characters were also unsatisfactory to define Hisonotus.
Several molecular (e.g. Chiachio et al. 2008;Cramer et al. 2011;Roxo et al. 2014a) and morphological (e.g. Martins et al. 2014) studies suggested that Hisonotus was polyphyletic, with H. insperatus Britski & Garavello, 2003, H. luteofrenatus Britski & Garavello, 2007, H. oliveirai Roxo, Zawadzki & Troy, 2014b, H. paresi Troy, 2014b andH. piracanjuba Martins &Langeani, 2012 belonging to a lineage unrelated to the one that includes the type species, H. notatus Eigenmann & Eigenmann, 1889. In this way, the elucidation of the relationships of the members of the Hisonotus is important to understand the evolution of Otothyrinae as a whole, considering that this genus represents about 35% of the diversity of this subfamily. Herein, a new genus is proposed to accommodate the above-cited species of Hisonotus and three additional new species are described in this new genus.

Material and methods
Measurements and counts were taken from the left side of the fish, and were made from point to point to the nearest 0.01 mm with a digital caliper. Body plate and osteology nomenclature follows Schaefer (1997) and measurements follow Carvalho and Reis (2009), except for body depth at dorsal fin origin. Abbreviations used in the text followed Carvalho and Reis (2009). Morphometrics are given as percentages of standard length (SL), except for subunits of the head region that are expressed as percentages of head length (HL). Specimens were cleared and double stained (c&s) according to the method of Taylor and Van Dyke (1985). Vertebral counts also include the five vertebrae that comprise the Weberian apparatus and the compound caudal centrum phylogenetic position of Curculionichthys with the subfamily Otothyrinae according to Roxo et al. 2014a). In the present study, based in the information published in Roxo et al. (2014a) and in new morphological analyses, we propose the new genus, Curculionichthys, for re-allocation of five species described within Hisonotus: C. insperatus, C. luteofrenatus, C. oliveirai, C. paresi and C. piracanjuba (see Table 2) and include three new species: C. sabaji, C. coxipone, and C. sagarana. Four putative additional species are recognized in the analyzed material, but these species cannot be described yet due to the lack of sufficient specimens.
The new genus Curculionichthys is defined by the following combination of characters: (1) a pair of rostral plates at the tip of the snout; (2) the presence of two large pre-nasal plates just posterior to the rostral plates; (3) a supra-opercular plate that receives the laterosensory canal from the compound pterotic before the preopercle; (4) a well developed sexual dimorphic membrane at anal opening in females; and (5) the presence of a V-shaped spinelet. The tip of the snout that is composed of a pair of rostral plates (Fig. 2) was first reported in species of Hisonotus by Britski and Garavello (2003) in the description of H. insperatus (C. insperatus), the type species of the new genus Curculionichthys. This character state according to Martins and Langeani (2012) is shared with Corumbataia cuestae Britski, 1997, species of Microlepidogaster Eigenmann & Eigenmann, 1889(except M. longicolla Calegari & Reis, 2010, Otothyris Myers, 1927, andin all genera of Hypoptopomatinae (except in Hypoptopoma Gunther, 1868). We also observed that Rhinolekos capetinga, a species recently described from the Rio Tocantins basin, also have a pair of rostral plates. However, the morphology of this character in the species of Curculionichthys is different, as described by Martins and Langeani (2012), since the rostral plates are very large, the length of each plate is greater than their width and are more conspicuous when compared with all species listed previously in which the pair of rostral plates is smaller and have a quadrangular form.
The second character used to diagnose the new genus is the presence of two large pre-nasal plates just posterior to the rostral plates (Fig. 2). The pre-nasal plates present some variation in members of Otothyrinae, with respect to their numbers and shapes. In most species of Otothyrinae the pre-nasal plates are small or very tiny, however in species of Curculionichthys we found two very large pre-nasal plates just posterior to the rostral plates. However, even in species of Curculionichthys we can find variation in pre-nasal plates contacting the frontal and the nasal plates, but the two large prenasal plates just posterior to the rostral plate apparently is a synapomorphic character exclusive to Curculionichthys.
The presence of a supra-opercular plate that receives the laterosensory canal from the compound pterotic before the preopercle is the third character used to diagnose the new genus. According to Martins and Langeani (2012) this character is present in a large number of species of Loricariidae, but absent in the Hypoptopomatinae and Otothyrinae, except in the new genus Curculionichthys. The fourth character is the presence of a well developed membrane at anal opening in females. Both sex of Curculionichthys species have a membrane on the anal opening, however, it is more developed in females than in males, covering almost the entire urogenital opening. This character was first reported by Roxo et al. (2014b) in the description of C. oliveirai and C. paresi and it is absent in all other species of Otothyrinae, in which the membrane at anal opening is poorly developed (see Fig. 4 in Roxo et al. 2014b for illustration about this character states).
The fifth character used to diagnose Curculionichthys was the presence of a Vshaped spinelet in the dorsal fin. This character was first reported by Carvalho and Datovo (2012) in the description of H. bockmanni in personal communication with Roberto E. Reis. This character is not exclusive to Curculionichthys and it is shared with H. acuen, H. chromodontus, H. vespuccii and two new species of Parotocinclus, one from Xingu basin (LBP 15894) and the other one from Barra do Garça (LBP 12274). Furthermore, the V-shaped spinelet is shared with vast majority of Hypostominae species ). However, within Otothyrinae it is good character that distinguishes the new genus.
In the description of C. oliveirai and C. paresi, Roxo et al. (2014b) found variation in head plate shape and number in the last two species and in C. insperatus, even though osteological characters are generally conserved within Otothyrinae and Hypoptopomatinae (Schaefer 1987(Schaefer , 1997(Schaefer , 1998bGaravello 1977;Mo 1991;de Pinna 1998;Diogo et al. 2001;Ribeiro et al. 2005). Roxo et al. (2014b) analyzed 18 specimens of C. insperatus from type localities in Rio Capivara and Rio Araquá, from Botucatu, São Paulo State, three individuals presented a single rostral plate, instead of a pair of rostral plates (see Fig. 8 in Roxo et al. 2014b for variation of all characters). In C. oliveirai and C. insperatus the authors found bilateral asymmetry in the first infraorbital and the first and second posterior rostral plates and in an extra plate is found between preopercle and compound pterotic (known in the present study as our third character: a supra-opercular plate that receives the laterosensory canal from the compound pterotic before the preopercle). Despite the variation observed among specimens of Curculionichthys, those characters appear to be conserved enough to be used as synapomorphies and delimit this new genus of all remaining Otothyrinae.

Description of three new species
Curculionichthys sabaji sp. n. http://zoobank.org/48C22C5D-2C7E-4ED5-AD1C-C3DF6568F322 Figure 3; Table 1 Holotype  Diagnosis. Curculionichthys sabaji differs from all congeners by having several dark-brown spots distributed on the body (vs. a variety of pigment patterns, but none of which includes dark-brown spots). Moreover, the new species differs from all congeners, except C. coxipone and C. paresi by having the cleithrum with an area free of odontodes, Fig. 4A (vs. cleithrum completely covered with odontodes, Fig. 4D-F). The new species further differs from C. piracanjuba, C. sagarana, and C. oliveirai by having some papillae of the lower lip arranged in a medial longitudinal series extending posterior to dentaries through the middle portion of the lower lip (vs. lower lip with all papillae randomly distributed); from C. coxipone and C. oliveirai by having the anterior profile of the head pointed (vs. rounded); from C. piracanjuba by having odontodes forming longitudinally aligned rows on head and trunk (vs. odontodes not forming longitudinally aligned rows on head and trunk); from C. insperatus and C. sagarana by having the caudal fin hyaline, with one dark strip extending from caudal peduncle base to the median caudal fin rays, and for dark chromatophores irregular distributed almost forming two bands, Fig. 5A (vs. caudal fin hyaline, with dark blotch limited to caudal peduncle base, Fig. 5B and 5C respectively); from C. sagarana by the absence of one unpaired platelet on the dorsal portion of caudal peduncle (vs. one unpaired platelet on the dorsal portion of the caudal peduncle, Fig. 6); from C. insperatus by having small, inconspicuous odontodes forming rows on the head and trunk (vs. large, conspicuous odontodes forming rows on the head and the trunk); from C. oliveirai by having 6−9 lateral abdomen plates (vs. 4−5 lateral abdomen plates); from C. paresi by lacking contrasting dark geometric spots on the anterodorsal region of body (vs. presence of geometric spots); from C. piracanjuba by not having hypertrophied odontodes on the snout tip (vs. hypertrophied odontodes on the snout tip). Additionally, Curculionichthys sabaji is distinguished by having a shorter dorsal fin spine (   Description. Morphometric and meristic data are given in Table 1. Small-size loricariid; maximum body length reached 23.6 mm SL. In lateral view, dorsal profile of body straight from snout tip to interorbital region; slightly convex to dorsal fin origin; and almost straight and decreasing to end of caudal peduncle. Ventral surface of body concave at tip of snout to anal fin insertion; concave to caudal fin insertion. Greatest body depth at dorsal fin origin. Greatest body width at opercular region; progressively narrowing towards snout and caudal fin. Trunk and caudal peduncle almost ellipsoid; rounded laterally and almost flat dorsally and ventrally. Head elliptical in dorsal view; snout long (45.5−56.9% HL), slightly pointed, its tip rounded, flat to slightly convex between orbits. Dorsal and ventral series of odontodes completely covering anterior margin of snout; odontodes of snout slightly larger in size than remaining ones found on head. Snout tip completely covered with odontodes. Odontodes on head and trunk well defined and arranged into longitudinal rows (one odontode after the other, but not necessarily forming parallel series). Eye small and round (10.2−17.9% HL), situated dorsolaterally in midpoint of head. Iris operculum present but poorly developed. No ridge between eyes and nares. Nostril small. Supraoccipital process not elevated and without tuft of odontodes in specimens of all size. Mouth wide; oral disk roundish with papillae arranged in a medial longitudinal series extending posterior to dentaries through middle portion of lower lip. Lower lip larger than upper; almost reaching cleithrum region; its border strongly fringed. Maxillary barbel short, slender and free distally. Teeth slender and bicuspidate. Cusps symmetrical; medial cusp larger than lateral. Premaxillary teeth 7-12. Dentary teeth 5-12.   Dorsal fin rays ii, 7; in lateral view dorsal fin originating slightly posterior through origin of pelvic fin; distal margin slightly convex. Tip of adpressed dorsal fin rays surpassing end of anal fin base. Dorsal fin spinelet short and V-shaped (Fig. 7A); lock mechanism functional. Pectoral fin rays i, 6; tip of longest tip of longest pectoral-fin ray almost reaching pelvic fin insertion, when adpressed. Pectoral axillary slit present between pectoral fin insertion and lateral process of cleithrum. Pelvic fin rays i, 5; distal margin slightly convex; tip of adpressed pelvic fin almost reaching anal fin origin. Adipose-fin absent. Anal fin rays i, 4; distal margin slightly convex. Caudal fin rays i, 7-7, i; slightly emarginate; both unbranched rays of same size. Adpressed rays of all fins covered with pointed odontodes. Total vertebrae 28.
Body completely covered by bony plates, except on ventral part of head, around pectoral and pelvic fin origins and on dorsal fin base. Abdomen entirely covered by plates (Fig. 7B), abdomen formed by lateral plate series with elongate and large plates, formed by two lateral plates series, similar in size; median plates formed by one to three plates series reaching anal shield. Lateral of body entirely covered by plates (Fig. 7C); mid-dorsal plates poorly developed, almost reaching end of dorsal fin base; median plates not interrupted in median portion of body; mid-ventral plates almost reaching middle of caudal peduncle. Cleithrum and coracoid totally exposed. Arrector fossae partially enclosed by ventral lamina of coracoids.
Color in alcohol. Ground color of dorsal and ventral region of head and trunk pale yellowish; dorsal portion darker than ventral. Four dark saddle along dorsal portion of body: one at dorsal fin origin; second at end of dorsal fin; third at middle of caudal peduncle; and fourth at upper caudal peduncle adpressed ray origin. Dorsal end ventral surface covered with small dark-dots smaller then eyes diameter. Unpigmented portion of snout appears as two hyaline parallel stripes from rostral plate to nares. Dorsal, pectoral, and pelvic fins with dark chromatophores forming irregular sets of bands: three on dorsal and pectoral fin, two on pelvic fin and one on anal fin. Caudal fin hyaline, except for dark stripe on origin of rays, and for dark chromatophores irregularly distributed forming two diffuse bands.
Sexual dimorphism. Adults males have a papilla in urogenital opening (vs. absent in females); have a long pelvic fin that extends beyond anal fin origin (vs. pelvic fin not reaching anal fin origin in females); and have an unbranched pelvic fin ray supporting a dermal flap along its dorsal surface. Both sexes have a membrane on anal opening; however, this membrane is more developed in females than in males, covering almost the entire urogenital opening (see reference to this last character in Roxo et al. 2014b).

Distribution.
The new species C. sabaji are known from five localities in the Rio Xingu basin: two at Rio 13 de Maio, one at Rio Coronel Vanick, one at Rio Couto de Magalhães and one at Rio Curuá (Fig. 8).
Etymology. The specific name "sabaji" is a patronym honoring Dr. Mark Henry Sabaj Pérez, Collection Manager of Ichthyology, Academy of Natural Sciences of Philadelphia, in recognition of his dedication and contributions to study of Neotropical fishes especially from Rio Xingu basin (iXingu Project).
Comparative remarks. Curculionichthys sabaji from the Xingu basin is morphologically very similar to C. paresi from Rio Paraguai basin. Both species share a low number of teeth in the premaxillaries and dentaries, the form of papillae in the lower lip and the general pattern of body coloration. However, C. sabaji, can be distinguished from C. paresi by having several dark-brown spots distributed on the body, a shorter dorsal fin spine, a shorter pectoral fin spine, a deeper caudal peduncle and the lack of dark geometric spots on the anterodorsal region of body. The similarity in morphology among both species suggests a close relationship between them and that they may have once shared a common ancestor. Furthermore, the presence of these close related species in the Rio Paraguay and the Rio Xingu is not a surprise, since several authors (e.g. Pearson 1937;Carvalho and Albert 2011) historically have reported that those two hydrographic systems share several lineages of fishes, and that most species lineage present in the Rio Paraguay originated in Amazonian drainages (Carvalho and Albert 2011).
Curculionichthys coxipone sp. n. http://zoobank.org/66B213A7-69B9-4980-B4EB-B7AFEEE43D5F Figure 9; Table 1 Hisonotus sp. 5 - Roxo et al. 2014a: 9(8)  Diagnosis. Curculionichthys coxipone differs from all congeners by having a higher number of vertebrae 29−30 (vs. 28 in all other species of Curculionichthys). The new species differs from all congeners, except C. sabaji and C. paresi by having the cleithrum with an area free of odontodes, Fig. 4B (vs. cleithrum completely covered with odontodes, Fig. 4D−F). The new species further differs from all congeners, except C. oliveirai by having the anterior profile of the head rounded (vs. pointed); from C. piracanjuba, C. sagarana, and C. oliveirai by having lower lip with some papillae arranged in a medial longitudinal series extending posterior to dentaries through middle portion of lower lip (vs. lower lip with all papillae randomly distributed); from C. insperatus and C. oliveirai by having the caudal fin hyaline, with one dark stripe extending from the caudal peduncle base to the middle caudal fin rays, and dark chromatophores irregular distributed almost forming one band, Fig. 5D (vs. caudal fin hyaline, with dark blotch limited to caudal peduncle base, Fig. 5B and E, respectively); from C. paresi by lacking contrasting dark-brown geometric spots on the anterior region of the body (vs. presence of dark-brown geometric spots); from C. sabaji by lacking several dark-brown spots distributed on the body (vs. presence of dark-brown spots); from C. oliveirai and C. coxipone by having the anterior profile of the head pointed (vs. rounded); from C. oliveirai by having 7−9 lateral abdomen plates (vs. 4−5 lateral abdomen plates); from C. paresi by having more dentary teeth 9−13 (vs. 4−7); from C. oliveirai by having 6−9 lateral abdomen plates (vs. 4−5 lateral abdomen plates); from C. sagarana by absence of one unpaired platelets on dorsal portion of caudal peduncle (vs. presence of one unpaired platelets on dorsal portion of caudal peduncle, Fig. 6); from C. piracanjuba by having some papillae on the lower lip arranged in a medial longitudinal series extending posterior to the dentaries through the middle portion of lower lip (vs. lower lip with all papillae randomly distributed) and by not having hypertrophied odontodes on the snout tip (vs. hypertrophied odontodes on the snout tip); from C. insperatus by having small, inconspicuous odontodes forming rows on the head and trunk (vs. large, conspicuous odontodes forming rows on the head and the trunk). Additionally, C. coxipone is distinguished by having a shorter interorbital distance ( Description. Morphometric and meristic available in Table 1. Small loricariid; bigger specimen examined reached 29.9 mm SL. In lateral view, dorsal profile of head convex from snout tip to posterior margin of parieto supraoccipital, and straight to dorsal fin origin. Dorsal profile of trunk slightly concave and descending from dorsal fin origin to end of dorsal fin base, straight to caudal peduncle. Ventral profile concave from snout tip to opercular region; convex from opercular region to anal fin origin; concave to caudal fin insertion. Greatest body depth at dorsal fin origin. Greatest body width at opercular region, gradually decreasing towards snout and caudal fin. Crosssection of trunk and caudal peduncle almost ellipsoid; rounded laterally and almost flat dorsally and ventrally. Head rounded in dorsal view; snout round to slightly pointed, its tip rounded, elongated (48.0−52.9% HL), slightly convex between orbits. Dorsal and ventral series of odontodes along anterior margin of snout completely covering its tip; odontodes at same size than remaining ones on head. Odontodes on head and trunk hypertrophied and arranged in longitudinal rows (most prominent on head). Eyes moderately small (12.0−16.4% HL), dorsolaterally positioned. Lips roundish with papillae arranged in a medial longitudinal series extending posterior to dentaries through middle portion of lower lip. Lower lip larger than upper lip; its border fringed. Maxillary barbel present; joined to lower lip. Teeth slender and bicuspid; medial cusp larger than lateral cusp. Premaxillary teeth 7−15. Dentary teeth 7−16.
Dorsal fin ii, 7; dorsal fin spinelet short and V-shaped (Fig. 10A); dorsal fin lock functional; dorsal fin origin slightly posterior to pelvic fin origin. Tip of adpressed dorsal fin reaching anal fin insertion. Pectoral fin i, 6; its tip reaching beyond pelvic fin insertion when depressed. Presence of pectoral axillary slit between pectoral fin insertion and lateral process of cleithrum variable; absent in some specimens. Pectoral spine supporting odontodes on ventral, anterior and dorsal surfaces. Pelvic fin i, 5; tip of pelvic fin unbranched ray almost reaching anal fin origin when depressed in females and reaching anal fin origin in males. Pelvic fin unbranched ray with dermal flap along dorsal surface in males. Anal fin i, 5; distal margin slightly convex. Caudal fin i, 7-7, Body covered with bony plates, except above head, around pectoral and pelvic fin origins and on dorsal fin base. Cleithrum and coracoid partially exposed. Arrector fossae partially to completely enclosed by ventral lamina of coracoids. Abdomen entirely covered by plates (Fig. 10B); lateral plates series with elongated and large plates formed by two lateral plate series, similar in size; median plates formed by six to seven irregular plate series reaching anal shield and lateral plate series; anal plates series covered by large square plates. Body entirely covered laterally by plates (Fig. 10C); mid-dorsal plates poorly developed and reaching middle of dorsal fin base; median plates series continuous in median portion of body; mid-ventral plates reaching of caudal peduncle origin.
Color in alcohol. Ground color of dorsal and ventral region of head and trunk pale yellowish; dorsal portion darker than ventral. Four dark saddle along dorsal portion of body: first at dorsal fin origin; second at end of dorsal fin; third at middle of caudal peduncle; and fourth at end of caudal peduncle. Unpigmented portion of snout appears as two hyaline parallel stripes from rostral plate to nares. Dorsal, pectoral, and pelvic fins hyaline. Caudal fin hyaline, with dark stripe extending from caudal peduncle base onto base of median caudal fin rays, and with dark chromatophores forming one large band.
Sexual dimorphism. Adults males have a papilla in urogenital opening (vs. absent in females); and have an unbranched pelvic fin ray supporting a dermal flap along its dorsal surface. Both sexes have a membrane on the anal opening; however, this membrane is more developed in females than in males, covering almost the entire urogenital opening (see reference to this last character in Roxo et al. 2014b).
Distribution. The new species C. coxipone is known from Rio Cuiaba drainage, Rio Paraguay basin, Mato Grosso State in Brazil (Fig. 8).
Etymology. The specific name "coxipone" refers to the Coxiponé indigenous people who inhabit the margins of Rio Cuiabá, near to the municipality of Cuiabá in Mato Grosso State, Brazil. A noun in opposition.
Comparative remarks. Curculionichthys coxipone is similar in external morphology with C. oliveirai from Rio Ivaí, upper Rio Paraná basin. However, the new species C. coxipone can be distinguished from C. oliveirai by having the cleithrum with an area free of odontodes, a higher number of vertebrae 29−30 and by a hyaline caudal fin, with one dark stripe extending from the caudal peduncle base to the median caudal fin rays, and for dark chromatophores irregular distributed almost forming one band. Furthermore, the presence of a higher number of vertebrae appears to be unique to C. coxipone.

Diagnosis.
Curculionichthys sagarana differs from all congeners by having one unpaired platelet on the dorsal portion of the caudal peduncle, Fig. 6 (vs. dorsal portion of caudal peduncle without unpaired platelets). The new species can be further distinguished from all congeners, except C. insperatus and C. luteofrenatus by having the caudal fin hyaline, with dark blotch limited to caudal peduncle base, Fig. 5C (vs. caudal fin hyaline, with one dark stripe extending from caudal peduncle base to the middle caudal fin rays, and for dark chromatophores irregularly distributed almost forming one or two bands); from C. insperatus, C. paresi and C. sabaji by having more premaxillary teeth 15−19 (vs. 10−12 in C. insperatus; 6−10 in C. paresi and 7−12 in C. sabaji) and more dentary teeth 12−18 (vs. 8−12 in C. insperatus, 4−7 in C. paresi and 7−12 in C. sabaji); from all congeners, except C. piracanjuba and C. oliveirai, by having all papillae on the lower lip randomly distributed (vs. lower lip with some papillae arranged in a medial longitudinal series extending posterior to dentaries through middle portion of lower lip); from C. oliveirai and C. coxipone by having the anterior profile of the head pointed (vs. rounded); from C. paresi by lacking contrasting darkbrown geometric spots on the anterodorsal region of the body (vs. presence); from C. piracanjuba by having odontodes forming longitudinally aligned rows on the head and trunk (vs. odontodes not forming longitudinally aligned rows on the head and trunk); from C. sabaji, C. coxipone and C. paresi by having the cleithrum completely covered with odontodes, Fig. 4D (vs. the cleithrum with an area free of odontodes, Fig. 4A−C); from C. insperatus by having small, inconspicuous odontodes forming rows on the head and trunk (vs. large, conspicuous odontodes forming rows on the head and the trunk); from C. oliveirai by having 6−9 lateral abdomen plates (vs. 4−5 lateral abdomen plates); from C. piracanjuba by not having hypertrophied odontodes on the snout tip (vs. hypertrophied odontodes on the snout tip). Additionally, C. sagarana is distinguished by having a deeper caudal peduncle (8.4−9.6 % of SL, vs. 10.8−12.5% of SL in C. oliveirai; 10.2−11.3% in C. paresi); a greater head length  Description. Morphometric and meristic available in Table 1. Small loricariid; largest examined specimen reaching 24.2 mm SL. In lateral view, dorsal profile of head convex from snout tip to posterior margin of parietosupraoccipital, and straight to dorsal fin origin. Dorsal profile of trunk slightly concave and descending from dorsal fin origin to end of dorsal fin base, straight to caudal peduncle. Ventral profile concave from snout tip to opercular region; convex from opercular region to anal fin origin; concave to caudal fin insertion. Greatest body depth at dorsal fin origin. Greatest body width at opercular region, gradually decreasing towards snout and caudal fin. Cross-section of trunk and caudal peduncle almost ellipsoid; rounded laterally and almost flat dorsally and ventrally.
Head elliptical in dorsal view; snout round to slightly pointed, its tip rounded, elongated (46.3−52.4% HL), slightly convex between orbits. Dorsal and ventral series of odontodes along anterior margin of snout completely covering its tip; odontodes at same size than remaining ones on head. Odontodes on head and trunk hypertrophied and arranged in longitudinal rows (most prominent on head). Eyes moderately small (13.8−16.3% HL), dorsolaterally positioned. Lips roundish with papillae arranged in a medial longitudinal series extending posterior to dentaries through middle portion of lower lip. Lower lip larger than upper lip; its border fringed. Maxillary barbel present; joined to lower lip. Teeth slender and bicuspid; medial cusp larger than lateral cusp. Premaxillary teeth 15−19. Dentary teeth 12−18.
Dorsal fin ii, 7; dorsal fin spinelet short and V-shaped (Fig. 12A); dorsal fin lock functional; dorsal fin origin slightly posterior to pelvic fin origin. Tip of adpressed dorsal fin reaching anal fin insertion. Pectoral fin i, 6; its tip reaching beyond pelvic fin insertion when depressed. Presence of pectoral axillary slit between pectoral fin insertion and lateral process of cleithrum variable; absent in some specimens. Pectoral spine supporting odontodes on ventral, anterior and dorsal surfaces. Pelvic fin i, 5; tip of pelvic fin unbranched ray almost reaching anal fin origin when depressed in females and reaching anal fin origin in males. Pelvic fin unbranched ray with dermal flap along dorsal surface in males. Anal fin i, 5; distal margin slightly convex. Caudal fin i, 7-7, i; slightly emarginate; both unbranched rays of same size. Adipose fin absent. Total vertebrae 28.
Body covered with bony plates, except above head, around pectoral and pelvic-fin origins and on dorsal fin base. Cleithrum and coracoid entirely exposed. Arrector fossae partially to completely enclosed by ventral lamina of coracoids. Abdomen entirely covered by plates (Fig. 12B); lateral plates series with elongate and large plates formed by two lateral plate series, similar in size; median plates formed by two to three irregular plate series reaching anal shield and lateral plate series; anal plates series covered by large square plates. Body entirely covered laterally by plates (Fig. 12C); mid-dorsal plates poorly developed and reaching end of dorsal fin base; median plates series continuous in median portion of body; mid-ventral plates reaching caudal peduncle origin. Dorsal portion of caudal peduncle with one unpaired platelet.
Color in alcohol. Ground color of dorsal and ventral region of head and trunk pale yellowish; dorsal portion darker than ventral. Four dark saddles along dorsal portion of body: first at dorsal fin origin; second at end of dorsal fin; third at middle of caudal peduncle; and fourth at upper caudal peduncle adpressed ray origin. Dorsal, pectoral, and pelvic fins hyaline. Caudal fin hyaline, with dark blotch limited to caudal peduncle base, and with dark chromatophores irregular distributed almost forming one band.
Sexual dimorphism. Adults males have a papilla in urogenital opening (vs. absent in females); a longer pelvic fin that extends beyond anal fin origin (vs. pelvic fin not reaching anal fin origin in females); nares opening wider (vs. nares opening narrower); and an unbranched pelvic fin ray supporting a large dermal flap along its dorsal surface. Both sex have a membrane on anal opening; however, this membrane is more developed in females than in males, covering almost the entire urogenital opening (see reference to this last character in Roxo et al. 2014b).

Distribution.
The new species C. sagarana are known from two localities along Rio das Velhas drainage: one at Rio 13 de Maio, one at Pardo Grande, and one at Rio Curimataí, all in Rio São Francisco basin, Minas Gerais State, Brazil (Fig. 8).
Etymology. The specific name "sagarana" is a hybrid of two words, "saga" of Germanic origin that means heroic song and "rana" from Tupi-Guarani language that means "similarity". The word sagarana is in reference to the book of a Brazilian author João Guimarães Rosa published in 1946 about the history of people from Minas Gerais State living in the region of Rio das Velhas.
Comparative remarks. The new species C. sagarana is similar in external morphology with C. insperatus, primarily the general pattern of coloration of the body. However, C. sagarana can be distinguished by the presence of one unpaired platelet on the dorsal portion of caudal peduncle, a character apparently present only in this new species, more premaxillary and dentary teeth, and small, inconspicuous odontodes forming rows on the head and trunk.