Otocinclus cocama, Reis, 2004

Reis, Roberto E., 2004, Otocinclus cocama, a new uniquely colored loricariid catfish from Peru (Teleostei: Siluriformes), with comments on the impact of taxonomic revisions to the discovery of new taxa, Neotropical Ichthyology 2 (3), pp. 109-115 : 110-112

Otocinclus cocama , new species

Figs. 1-4

Holotype. MUSM 20686 , 43.5 mm SL, female, quebrada Yanayacu (approx. 04°55’S, 073°43’W), tributary to the caño of the cocha Supay in Jenaro Herrera , Provincia Requena, Departamento Loreto, Peru; Jan 2004, employees of Mr. Grimaldo Mendoza Oviedo collected.

Paratypes. MUSM 20687 (5, 29.6-43.2 mm SL), MCP 34842 (8, + 2 c&s, 29.8-40.7 mm SL + 1 tissue sample), and AMNH 233730 (3, 36.4-43.8 mm SL), all collected with the holotype.

Diagnosis. The following putative autapomorphies distinguish Otocinclus cocama from all its congeners: (1) a unique, distinct color pattern consisting of vertically elongated blotches spanning from the dorsal midline to the ventral border of flanks ( Figs. 1 and 4 ), and (2) a complete lateral line, without the gap plates (midbody plates without lateral line perforations) present in other Otocinclus . In addition, the new species can be distinguished from most other Otocinclus by its high number of teeth (30-45 in premaxilla and 23-36 in dentary vs. 10-29 and 9-22 in most species except O. huaorani Schaefer, 1997 [18-34 and 16-30], O. mura Schaefer, 1997 [22-30 and 18- 27], and O. bororo Schaefer, 1997 [17-31 and 17-26]). From O. huaorani , O. mura , and O. bororo , the new species can be further distinguished by the presence of a small metapterygoid channel (vs. absent in these three species), and by having one W-shaped mark in the caudal fin (vs. two W-shaped mark in the above three species).

Description. Standard length of examined specimens 29.6- 43.8 mm SL. Other morphometric data presented in Table 1, counts in Table 2.

Body moderately short, robust. Dorsal profile of head from snout tip to dorsal-fin origin straight to slightly convex; slightly concave between snout tip and nares. Dorsal profile of trunk from dorsal-fin origin to caudal peduncle straight to slightly concave. Ventral profile of head and abdomen from snout tip to anus straight, transversely flat. Ventral profile of trunk slightly concave between anal-fin origin and caudal fin. Snout rounded, rostrum convex; region anterior to nares slightly depressed. Greatest body depth at dorsal-fin origin, 19.8-24.9% SL. Body between pectoral and pelvic-fin origins ovoid in cross section; trunk ovoid and compressed in cross section anteriorly, progressing to slightly rectangular towards caudal fin. Dorsal and ventral surface of caudal peduncle slightly flattened; margins of dorsal and ventral lateral plate series bearing enlarged odontodes forming ridge-like keels, especially pronounced in smaller individuals.

Head depressed. Eyes moderately large, visible from ventral side. Orbit length 18.5-25.9% HL; positioned approximately midway between snout tip and compound pterotic posterior process; distance between orbit margin and ventral surface of head less than half orbit length. Dorsal iris diverticulum absent. Lateral ethmoid with small subnasal lamina.

Dorsal fin II, 7; origin approximately at or slightly beyond vertical through pelvic-fin origin; when depressed, reaching to vertical line through end of anal-fin base. Nuchal plate narrow, roughly triangular, articulated with V-shaped, dorsalfin spinelet; dorsal-fin locking mechanism functional. Pectoral fin I, 6; reaching to middle of pelvic fin length. Pectoral pore present on skin above pectoral-fin insertion, below lateral process of cleithrum. Pelvic fin I, 5; when depressed reaching beyond anus but not reaching anal-fin origin; skin flap on dorsal surface of unbranched pelvic-fin ray of males. Anal fin I, 5. Caudal fin I, 7/7, I; upper caudal fin lobe slightly longer than lower one. Dorsal procurrent rays 4-5; ventral procurrent rays 5 (in two c&s specimens).

Total plates in middle lateral series 22-24, usually 23. Lateral line almost complete, pored tubes visible from compound pterotic to caudal peduncle; 1-3 most posterior plates in middle series without lateral line. Total vertebrae 28 (in two c&s specimens). Abdomen completely covered by paired series of 4-7 (usually 5-6) large, sickle-shaped lateral plates, intervening region covered by smaller, squarish to rounded plates of irregular size and spacing, usually arranged in 1-2 longitudinal series; median plates extending posteriorly beyond lateral abdominal plate series to middle of branched pelvic fins forming triangular pre-anal shield. Subopercular plate present and well developed. Pelvic girdle completely exposed ventrally and covered with odontodes; arrector fossae closed.

Odontodes evenly distributed and regularly arranged on head and body. Enlarged odontodes on anterior and lateral snout margin, dorsal-, pectoral-, and pelvic-fin spines, and in row along lateral corners of slightly flattened dorsal and ventral caudal peduncle region. Males with small contact organ formed by swirl of odontodes ( Fig. 3 ) at ventral margin of caudal fin base.

Premaxillary teeth 30-45, mandibular teeth 23-36. Oral disk roundish, covered with small papillae; margin of lower lip heavily fringed; maxillary barbel short, its free portion about one fourth to one third of orbit length.

Color in life. Ground color of head and dorsum bluish white to slightly creamy yellowish. Dorsum of head and snout between nares black. Lateral portions of snout and postorbital region of head also black, leaving narrow, V-shaped white band beginning at snout tip, passing through nares and above orbits, and progressing laterally through compound pterotic. Ventral margin of snout darkened but head otherwise white or pale yellowish ventrally. Medial portions of compound pterotic, parietosupraoccipital, and first pre-dorsal plate black or dark gray. Color pattern of dorsum of body and flanks formed by four black or dark gray, saddle-shaped blotches; one at origin of dorsal fin, second behind dorsal-fin base, third between dorsal and caudal fins, and fourth at base of caudal fin. These dorsal markings always prolonged ventrally into flanks, in wide, vel- Loreto, Peru (Fig. 5). This species has been in the aquarium trade since early 2001 and is quite common in the aquarium shops in Iquitos, Peru, being likely to occur in other places in lower Ucayali and Marañon rivers.

Ecology. The type locality of Otocinclus cocama is a medium size creek, with clear water and lots of marginal vegetation. According to the collectors, the fishes are usually caught by seining and dipnetting in that vegetation.

vet black, transverse bands, usually duplicated or forming roundish blotches in large specimens ( Fig. 4 ). Additional layer of dark gray pigment in subjacent skin form with lateral blotches inconspicuous lateral stripe. Some pigmentation sometimes scattered or forming few dots on lateral portion of belly, between pelvic and anal fins, and on ventral face of caudal peduncle. Fins mostly hyaline. Outer face of pectoral spine pigmented with black; small patch of black chromatophores on unbranched pelvic- and anal-fin rays, sometimes on first branched anal-fin ray. Dorsal fin black at origin and with wide transverse, roughly triangular black band from spine to last branched ray, but leaving base and tip of rays white. Black spot on dorsal-fin spine and first branched ray sometimes divided in two patches. Caudal fin with W-shaped vertical band in distal half, but leaving narrow hyaline band at margin. Base of two central caudal-fin rays usually black, as prolongation of last caudal peduncle black blotch ( Fig. 2 ).

Etymology. Otocinclus cocama is named after the Cocama- Cocamilla Indians that used to be dominant in the lower Ucayali and Marañon rivers. The present estimations point to a little more than 10,000 people in Peru, plus a few hundreds in Colombia and Brazil. During the last century, the Cocama culture has been mostly assimilated by the regional society, losing their language and identity, being thus threatened as a group. The name is treated as a noun in apposition.

Figures

Fig. 1. Otocinclus cocama, holotype, MUSM 20686, 43.5 mm SL, female, quebrada Yanayacu, Jenaro Herrera, Loreto, Peru.

Fig. 2. Caudal fin of Otocinclus cocama, holotype, MUSM 20686,43.5mm SL, female,quebradaYanayacu,Jenaro Herrera, Loreto, Peru.

Fig. 3. Caudal peduncle of Otocinclus cocama, paratype, MCP 34842, 36.2 mm SL. Odontode swirl forming a contact organ (arrow), a male sexual dimorphism in the arrangement of odontodes near the caudal-fin base.

Fig. 4. Live specimen of Otocinclus cocama, collected in Peru in 2000; not preserved. Photo by Ingo Seidel.