Rineloricaria atratoensis, Castellanos-Mejía & Londoño-Burbano & Ochoa & García-Alzate & DoNascimiento, 2024

Castellanos-Mejía, María Camila, Londoño-Burbano, Alejandro, Ochoa, Luz E., García-Alzate, Carlos A. & DoNascimiento, Carlos, 2024, Two New Species of Rineloricaria (Siluriformes: Loricariidae) from Trans-Andean Rivers of Colombia, Unveiled through Iterative Taxonomy, Ichthyology & Herpetology 112 (3), pp. 429-443 : 430-433

Rineloricaria atratoensis , new species urn:lsid:zoobank.org:act:82E4A522-A6C0-473A-839A-50CAF3A3BD86 Figures 1A , 2 ; Table 1

Rineloricaria magdalenae (not Steindachner). MaldonadoOcampo et al., 2006: 148 (in part: IAvH-P 6760).

Rineloricaria sp. Maldonado-Ocampo et al., 2006: 148 (in part: IAvH-P 7403).

Holotype.— CIUA 4629 , female, 113.8 mm SL, Colombia, Antioquia, Murindó, caño Chageradó, Atrato River basin, 06849 0 56 00 N, 76848 0 31 00 W, 8 m a.s.l., A. Loaiza, 15 March 2016.

Paratypes.— Colombia: Atrato River basin: Antioquia: CIUA 4767 , 3 , 88.4–108.9 mm SL, Murindó, caño Chageradó , 6849 0 56 00 N, 76848 0 31 00 W, 8 m a.s.l., A. Loaiza, 13 May 2015 ; CIUA 4770 , 16, 61.9–118.4 mm SL, Vigía del Fuerte, caño El Chorro , 6823 0 42 00 N, 76844 0 36 00 W, 21 m a.s.l., A. Loaiza, 8 May 2015 ; CIUA 8683 , 4, 108.8– 117.1 mm SL, same locality and collector as CIUA 4767, 15 March 2016 . Chocó: IAvH-P 614, 1, 132.7 mm SL, Atrato River , approx. 5842 0 N, 76837 0 W, 84 m a.s.l., P. A. Silverstone, 10 August 1971 ; IAvH-P 6760, 1, 126.3 mm SL, Atrato River , approx. 8817 0 N, 76858 0 W, 2 m a.s.l., Chaverra and Cuesta, 19 August 2004 ; IAvH-P 7279, 1, 100.6 mm SL, Atrato River , 7852 0 44 00 N, 77802 0 26 00 W, 3 m a.s.l., J. A. Maldonado-Ocampo, 17 July 2005 ; IAvH-P 7403, 1, 106.8 mm SL, Unguía River , 8803 0 36 00 N, 77807 0 21 00 W, 77 m a.s.l., J. A. Maldonado-Ocampo, 24 July 2005 .

Diagnosis.— Rineloricaria atratoensis is distinguished from all trans-Andean and Central American congeners by having the first (unbranched) ray of dorsal, pectoral, and pelvic fins extended as a short filament (vs. coterminous with branched rays in R. altipinnis , R. giua , new species, R. jubata , R. magdalenae , R. rupestris , R. sneiderni , and R. uracantha ). Rineloricaria atratoensis can also be distinguished from this group of species (except R. magdalenae ) by having a paired deep depression between the nostrils and the interorbital region (vs. absent in R. altipinnis , R. giua , new species, R. jubata , R. rupestris , R. sneiderni , and R. uracantha ). Rineloricaria atratoensis differs from R. altipinnis , R. giua , new species, R. magdalenae , R. sneiderni , and R. uracantha by having five plates along sides of dorsal-fin base (vs. four). Rineloricaria atratoensis differs from R. altipinnis , R. giua , new species, R. rupestris , R. sneiderni , and R. uracantha by having three rows of median abdominal plates (vs. four or more). The new species differs from R. rupestris , R. sneiderni , and R. uracantha by having six dark brown transverse bars on dorsal surface of body (vs. four or six). The new species is further distinguished from most of its congeners (except R. aurata , R. beni , R. cadeae , R. castroi , R. catamarcensis , R. felipponei , R. giua , new species, R. lanceolata , R. langei , R. longicauda , R. magdalenae , R. misionera , R. nigricauda , R. pareiacantha , R. parva , R. quadrensis , R. sanga , R. setepovos , R. sneiderni , R. stellata , R. strigilata , R. thrissoceps , R. uracantha , and R. wolfei ) by absence of the mid-dorsal plate series (vs. present in R. aequalicuspis , R. altipinnis , R. anhaguapitan , R. anitae , R. baliola , R. cacerensis , R. cachivera , R. capitonia , R. caracasensis , R. daraha , R. eigenmanni , R. fallax , R. formosa , R. hasemani , R. heteroptera , R. isaaci , R. jaraguensis , R. jubata , R. konopickyi , R. kronei , R. latirostris , R. maacki , R. malabarbai , R. maquinensis , R. melini , R. microlepidogaster , R. morrowi , R. nudipectoris , R. osvaldoi , R. pentamaculata , R. phoxocephala , R. platyura , R. reisi , R. rodriquezae , R. rupestris , R. steindachneri , R. stewarti , R. teffeana , R. tropeira , and R. zaina ). The new species differs from R. cadeae , R. castroi , R. catamarcensis , R. langei , R. lima , R. longicauda , R. misionera , R. nigricauda , R. pareiacantha , R. parva , R. quadrensis , R. sanga , R. setepovos , R. stellata , R. strigilata , and R. uracantha by breeding males with dimorphic odontodes on sides of head and on dorsum of pectoral fin (vs. breeding males lacking dimorphic odontodes). It is distinguished from R. aequalicuspis , R. anhaguapitan , R. anitae , R. aurata , R. baliola , R. capitonia , R. isaaci , R. jaraguensis , R. kronei , R. latirostris , R. maacki , R. malabarbai , R. maquinensis , R. microlepidogaster , R. pentamaculata , R. reisi , R. rupestris , and R. tropeira by having slender post-pectoral naked area (vs. wide).

Description.— Morphometric data in Table 1. Head and body depressed. Dorsal profile of head triangular. Snout elongated and tip rounded in dorsal view and straight (not raised) in lateral view ( Fig. 1A ). Naked area of snout tip transversally elliptical, not reaching first pore of infraorbital sensory canal. Dorsal profile convex from tip of snout to dorsal-fin origin, and straight to caudal-fin origin. Ventral profile straight from tip of snout to caudal-fin origin. Greatest body depth at posterior border of parieto-supraoccipital; lowest body depth along caudal peduncle ( Fig. 2 ).

Hypertrophied odontodes of head small to moderate size, forming conspicuous ridges between nostrils, on posterior nasal plates to posterior margin of parieto-supraoccipital and compound pterotic. Five plates in infraorbital series, with sensory pores exposed ventrally. Predorsal plates and first three lateral plates of dorsal series slightly keeled, covered with small odontodes. Eye elliptical with large and deep postorbital notch, equal to half horizontal diameter of orbit ( Fig. 1A ).

Upper lip short and separated from naked area of snout by thin row of plates covered by tiny odontodes. Margin of upper lip with long, rugged, and regular papillae. Anteroventral bor- der of upper lip separated from anterior border of premaxillary ramus by one row of papillae. Lower lip covered by irregular sized papillae, unorganized and distributed around oral cavity. Edge of lower lip with elongated, triangular fringes. Maxillary barbel long, with minute papillae. Teeth bicuspid and cusps rounded or slightly pointed; dentary teeth larger than premaxillary teeth. Premaxilla with 8(1), 10(1), 11(2)*, or 12(1) teeth; dentary with 9(1), 10(3)*, 11(2), or 12(1) teeth; accessory cusp almost of same size as main one.

Plates on median series 29(2), 30(6), or 31(2)*; coalesced plates 13(1), 14(3), or 15(6)*, lateral abdominal plates 5(1), 6(3), or 7(6)*; median abdominal plate rows 3(10)* ( Fig. 1A ). Lateral line complete. Mid-dorsal series absent. Lateral plates keeled with odontodes along lateral line. Abdomen totally covered by plates, including cleithral region ( Fig. 1A ). Abdominal plates organized in three sections: anterior abdominal plates small, quadrangular, covering pectoral girdle; median abdominal plates large and trapezoidal, between pectoral and pelvic girdles; posterior abdominal plates with preanal shield formed by three large plates surrounding polygonal preanal plate. Two plates along sides of anal-fin base.

Dorsal-fin rays i,7 (10), dorsal-fin spinelet present, locking mechanism not functional. Five plates along sides of dorsal-fin base. Pectoral-fin rays i,6 (10), adpressed unbranched ray slightly surpassing pelvic-fin origin. Pelvic-fin rays i,5 (10), adpressed unbranched ray reaching anal-fin origin. Anal-fin rays i,5 (10). Caudal-fin rays i, 5 þ 5,i (10); margin of fin emarginated, with long and thin filament on upper caudal-fin ray; lower caudal-fin ray filament absent.

Color in alcohol.— Background coloration of dorsal surface light brown. Pores of sensory system on head and lateral medial plates dark. Dorsal surface of body with six dark brown transverse bars; first at dorsal-fin origin, second at level of tip of adpressed dorsal fin, following posterior bars on caudal peduncle. All fins covered by dark dots on fin rays. Ventral surface pale yellow ( Fig. 2 ).

Distribution.— Rineloricaria atratoensis is only known from the Atrato River basin, draining directly to the Caribbean Sea, in northwestern Colombia ( Fig. 3 ).

Sexual dimorphism.— Adult males with hypertrophied odontodes on sides of head and on dorsum of pectoral fin.

Etymology.— The species name atratoensis is in reference to its type locality, the Atrato River.

Remarks.— Rineloricaria jubata and R. magdalenae were originally recorded from the Atrato River by Eigenmann (1922), and subsequent authors ( Mojica et al., 2004; Maldonado-Ocampo et al., 2006, 2012) have also listed these two species from the Atrato basin. Maldonado-Ocampo et al. (2006) recognized for the first time a third species of Rineloricaria from this basin, which was positively confirmed by us as R. atratoensis (IAvH-P 7403). However, another record listed by Maldonado-Ocampo et al. (2006) as R. magdalenae (IAvH-P 6760) turned out to be R. atratoensis , thus the presence of R. magdalenae as well as R. jubata in the Atrato River is the subject for confirmation in our ongoing systematic revision of Rineloricaria in Colombia.

Figures

FIG. 1. Head and abdominal area showing ventral plates in (A) Rineloricaria atratoensis, CIUA 4629, holotype, 113.8 mm SL; (B) R. giua, CIUA 8370, paratype, 78.9 mm SL; (C) R. magdalenae, CIUA 7549, 114.6 mm SL; (D) R. jubata, IMCN 4015, 110.3 mm SL; (E) R. rupestris, CZUT-IC 19074, 99.1 mm SL; (F) R. sneiderni, ANSP 71433, holotype, 122 mm SL. Photographs in A–E by José Luis Londoño-López, copyright Colección de Ictiología de la Universidad de Antioquia; used with permission. Photographs in F by Kyle Luckenbill, copyright Ichthyology Department, Academy of Natural Sciences; used with permission. Scale bar 1 cm.

FIG. 2. Holotype of Rineloricaria atratoensis, CIUA 4629, 113.8 mm SL, female, caño Chageradó, Atrato River basin, Murindó, Antioquia, Colombia, 684905600N, 7684803100W. Photograph by José Luis Londoño-López, copyright Colección de Ictiología de la Universidad de Antioquia; used with permission. Scale bar 1 cm.

FIG. 3. Map of north region of Colombia showing distribution of Rineloricaria atratoensis (dots) and R. giua (stars). White symbols: type localities.