Rineloricaria daraha, Rapp Py-Daniel & Fichberg, 2008

Rapp Py-Daniel, Lúcia H. & Fichberg, Ilana, 2008, A new species of Rineloricaria (Siluriformes: Loricariidae: Loricariinae) from rio Daraá, rio Negro basin, Amazon, Brazil, Neotropical Ichthyology 6 (3), pp. 339-346 : 340-344

Rineloricaria daraha , new species

Figs. 1-3

Holotype. INPA 28579, 200.9 mm SL (male), Brazil, Amazonas, rio Daraá, cachoeira do Aracu (00°25’00”S 064°46’59”W), 29 Nov 1991, R. Sotero & R. Ribeiro.

Paratypes. (20) Brazil, Amazonas, rio Daraá. INPA 6586 , 4 , 129.3 - 186.8 mm SL, same data as holotype. MZUSP 31396 , 1 c&s, 127.5 mm SL, female, cachoeira do Aracu, 10 Feb 1980, M. Goulding. MZUSP 35094 , 2 , 40.7-46.6 mm SL, females, cachoeira do Aracu , 10 Nov 1980, M. Goulding. INPA 6587 , 2 , 57.7-65.9 mm SL, cachoeira do Pacu , 1 Dec 1991, L. Aquino. INPA 12045 , 7 , 63.0- 117.4 mm SL, cachoeira do Pacu , 1 Dec 1991, L. Aquino. INPA 17939 , 3 , 41.3-74.5 mm SL, cachoeira do Aracu , 10 Nov 1980, M. Goulding, INPA 28780 , 1 , 75.0 mm SL, juvenile, rio Daraá , cachoeira do Panãpanã, 00°02’15.2”S 64°47’44”W, 4 Feb 2008, M. Rocha & V. Masson .

Diagnosis. Rineloricaria daraha is distinguished from all its congeners by having seven branched pectoral-fin rays (vs. six), long digitiform papillae on the ventral surface of the lower lip (vs. button-like papillae) and by the presence of a large and multi-angular preanal plate limited anteriorly by four or more variably sized plates much smaller than the preanal plate (vs. a quadrangular preanal plate surrounded by three to five polygonal plates slightly smaller than the preanal plate).

Description. Morphometric data in Table 1. Body elongated and depressed. Dorsal profile slightly convex from tip of snout to origin of dorsal fin. Body slender along its whole extension, tapering softly towards base of caudal fin. Ventral profile straight from tip of snout to pelvic fin. Lateral profile from pelvic fin to caudal fin becomes more depressed towards caudal-fin base where body becomes more flattened. Greatest body depth at dorsal-fin base.

Head elongated and depressed. Snout long (53-59% of head length) and pointed with small naked area. Naked area not reaching most anterior pore of infraorbital sensory canal. Orbit small and round, with deep and short lanceolate postorbital notch. Head variably keeled; when present, keel reduced to low ridge in front of eye.

Predorsal area not keeled, except by weak pair of carinae on last predorsal plate. Twenty seven lateral plates conspicuously carinated forming a keel. Two longitudinal and confluent keels meeting at 14 th plate of median series. From this point on, remaining thirteen carinated plates of both lateral series form single keel until base of caudal fin.

Mouth opening small and surrounded by short upper lip and well-developed lower lip. Margin of lip fringed with small filaments. Rictal region with well marked groove. Above groove, line of button-like papillae cover maxillary barbel. Papillae much longer at tip of maxillary barbel. Upper lip with few button-like papillae, lower lip surface covered (densely covered in some specimens) by long digitiform papillae, resembling short filaments. Digitiform papillae concentrated around mouth cavity. Small specimens (smaller than 50 mm SL) with round papillae on lip surface. Buccal papillae present behind dentaries; few buccal papillae on premaxillaries. Most of palate smooth, without papillae, except for straight line with three to five papillae, longitudinally oriented, situated at lateral tip of premaxillaries. Mandibular teeth short but robust, deeply forked: seven to eight teeth on premaxillaries and five to seven on dentaries. Dentary teeth larger than those on premaxilla.

Dorsal fin I,7, anterior and long, running along 8 or 9 dorsal plates; pectoral fin I,7 with spine almost straight on females or non-reproductive males, and thick and curved on mature or almost mature males. Pectoral fin reaching third plate of dorsal lateral series. Pelvic fin i,5 and anal fin i,5, welldeveloped. Pelvic fin reaching little beyond insertion of anal fin mostly in females; pelvic fin of males not reaching anal-fin insertion when adpressed. Pelvic unbranched ray thicker in mature males.Anal fin running along seven plates. Caudal fin i,10,i, bilobed to slightly emarginated, with upper lobe little longer than lower lobe. Dorsalmost caudal-fin ray bearing long and thick filament.

Abdominal surface completely covered by unorganized small quadrangular plates in adults, except for naked gular area. Five or six large lateral abdominal plates. Strong gradient of increasing plate size towards pelvic fin. Abdominal plates tightly packed and forming shield. Anterior borderline of this shield irregular, curved caudad in mid-line in some specimens. Preanal plate present, conspicuously larger than other plates and almost round in shape in some specimens. Preanal plate surrounded by at least four quadrangular plates of largely different sizes, with some much smaller than preanal plate itself. Abdominal plating development following ontogenetic process with young specimens showing abdomen largely naked, with few odontodes spread all over abdominal surface. Young adults (approximately 130 mm) with abdomen completely covered.

Color in alcohol. Light brown background densely covered with conspicuous black round spots on head; faded and irregularly shaped dark blotches on body. Most spots on head contain pores of cephalic sensory canal. Sphenotic and supraoccipital bordered by soft black connective tissue in recently preserved specimens. Two conspicuous black spots just above naked area behind cleithrum, spots surrounding one or two exits of lateral sensory canal. Five wide dark transverse bands on body: first just behind dorsal-fin base, three bands along caudal peduncle and last one close to caudal-fin base. Bands faded in some specimens. Ventral surface uniform. All fin rays irregularly stained of dark, forming large bands of just spots on fins. Interradial membranes hyaline. Dorsal, pectoral and caudal fins darkened at base.

Sex dimorphism. Mature males present the following features: large patch of thick enlarged odontodes on sides of the head; pectoral-fin spine thick and strongly curved; pectoral spine and rays heavily covered by enlarged series of odontodes; shorter snout and fins when compared to young and females ( Figs. 2 and 3). Dorsal, pectoral, pelvic and anal fins slightly longer on adult females than on mature males.

Distribution. The new species is only known from cataracts of the rio Daraá (cachoeira do Aracu, Pacu and Panãpanã), a tributary to the rio Negro, in the state of Amazonas, northwestern Brazil ( Fig. 4).

Etymology. The specific epithet daraha (Daraá in Portuguese) refers to the type locality.