Pseudobunocephalus lundbergi, Friel, 2008

Friel, John P., 2008, Pseudobunocephalus, a new genus of banjo catfish with the description of a new species from the Orinoco River system of Colombia and Venezuela (Siluriformes: Aspredinidae), Neotropical Ichthyology 6 (3), pp. 293-300 : 295-298

Pseudobunocephalus lundbergi , new species Fig. 4

Holotype. ANSP 168817 , 28.4 mm SL, Venezuela, Bolivar, caño Barranca, approximately 1.25 hours downstream from Jabillal (opposite bank) on río Caura , 07°08’N 65°04’W, 30 Jan 1977, J. Böhlke and W. Saul.

Paratypes. Venezuela, Bolivar, ANSP 172504 , 10 , 20.5 - 29.1 mm SL ; ANSP 172505 , 370 alcohol, 5 cleared & stained, 20.0-30.0 mm SL ; AUM 47713, 6 , 22.7 - 24.7 mm SL; CU 94217, 8, 25.6-28.1 mm SL ; FMNH 117789 , 6 , 20.5 - 27.1 mm SL ; INPA 29030 , 6 , 20.5 - 26.5 mm SL; MBUCV-V-35369, 6, 21.2-26.1 mm SL; all same data as holotype ; MCNG 21122 , 3 , 24.6 - 26.4 mm SL, forest stream 5 km N of Jabillal , 3 Mar 1989, D. Taphorn et al .; MCP 42737, 6 , 22.6 - 25.4 mm SL ; MZUSP 99617 , 6 , 20.5 - 25.1 mm SL ; USNM 393553 , 6 , 18.8 - 24.6 mm SL, same data as holotype .

Non-types. Colombia, Meta, ANSP 131574 , 4 , 19.5 - 22.5 mm SL, caño Rico at La Defensa, 03°59’N 73°08’W, 25 Feb 1972, J. Böhlke et al .; ANSP 134530 , 1 , 24.3 mm SL, ca. 5 km N of La Siberia , 04°07’N 73°05’W, 28 Mar 1975, J. Böhlke et al .; ANSP 168815 , 4 , 22.0-23.0 mm SL, caño La Raya, N of La Siberia, 04°50’N 73°05’W, 29 Mar 1975, J. Böhlke et al . Venezuela, Apure, MCNG 23671 , 13 (12 alcohol, 1 cleared & stained), 20.0-23.0 mm SL, río Meta between San Carlos de Meta and Buena Vista , 14 Jan 1982, D. Taphorn et al . Barinas, MCNG 23669 , 2 , 22.5 - 23 mm SL, Ticoporo forest, río Socopo basin, 9 Dec 1982, D. Taphorn et al .

Diagnosis. Pseudobunocephalus lundbergi can be distinguished from all congeners by having the following unique characters within the genus: dorsal surface of skull ornamented with numerous bony knobs of equal size ( Fig. 4 ); distinct anterior and posterior cranial fontanels separated by a bony epiphyseal bar formed between the frontals ( Fig. 3 ); infraorbital canal exits from the sphenotic ( Fig. 3 ) and extends anteriorly past eye, bearing up to four pores (not figured); premaxilla without a posterolateral limb; and fifth centra with posteriorly directed processes that articulate with skeletal elements of the dorsal fin.

Description. Dorsal, lateral and ventral views in Fig. 4 illustrate body shape and positions of fins and barbels. Morphometric and meristic data for holotype (ANSP 168817) and 10 syntopic paratypes (ANSP 172504) are summarized in Table 1. Head depressed with only slight depression between orbits. Skull ornamentation well developed with paired series of bony knobs beginning behind eyes, converging on occiput and continuing on dorsal lamina of Weberian complex and middle nuchal plate. All bony knobs approximately equal in size. Anterior and posterior cranial fontanels present and separated by bony epiphyseal bar formed by frontals ( Fig. 3 ). Integument covered with small unculiferous tubercles, those on posterior body in longitudinal rows; mid-dorsal row well defined; 2-3 well-defined rows on each side of caudal peduncle; several poorly-defined rows ventrally ( Fig. 4 ). Caudal peduncle slender, round in cross section, tapering to caudal fin.

Mouth terminal, anterior limits of upper and lower jaws approximately equal. Premaxilla with 5-6 rows of acicular teeth and lacks posterolateral process. Dentary with 12-15 rows of teeth restricted to patch near symphysis of lower jaw ( Fig. 1 ). Anterior nostril tubular, located at tip of snout, projecting beyond upper lip. Posterior nostril simple without flap or barbel, opening anteromedial to eye. Eye without free orbital rim. All barbels simple, unbranched; maxillary barbel reaching pectoral spine insertion. Posterolateral mental barbel at least twice as long as anteromedial mental barbel. Gular fold absent, branchiostegal membranes united to each other and to isthmus, 5 branchiostegal rays ( Fig. 1 ). Opercular opening reduced to small valvular slit on ventral surface just anterior to pectoral spine insertion.

Gill rakers absent on all branchial arches. Pharyngeal teeth well developed on upper tooth plate; 1 or 2 rows of teeth on lower tooth plates. First and second hypobranchials well ossified; fourth pharyngobranchials absent. Parurohyal triangular with slight dorsal keel.

Openings of sensory canals on head darkly pigmented. Infraorbital canal exits sphenotic ( Fig. 3 ) and passes anteriorly beyond eye, bearing up to four pores (not figured). Lateral-line canal truncated just posterior of parapophyses of fifth vertebra and anterior to dorsal-fin origin. A few individual isolated pores scattered more posteriorly, but never connected to main lateral-line canal.

Dorsal fin without spinelet; consists of relatively flexible spine and four soft rays. Dorsal-fin membrane not adnate with body. Anterior nuchal plate and supraneural absent. Middle nuchal plate ornamented with a single bony knob. Adipose fin absent. Anal fin with 5-7 soft rays (6 in holotype), anal-fin membrane not adnate with body. Pectoral fin with robust spine and 5 soft rays. Shaft of pectoral spine curved with serrations along both pre-axial and post-axial margins. Intact pectoral spine with flexible tip. Axial pore present. Postcoracoid process of pectoral girdle extends slightly past postcleithral process in lateral view. Pelvic fin with 6 soft rays, second and third rays longest, not reaching anal-fin origin, no pelvic splint. Caudal fin with 10 principal rays plus one upper and one lower procurrent ray. Caudal-fin margin rounded with outermost principal rays unbranched and shorter than branched principal rays.

Total vertebrae 33-34 (34 in holotype). Vertebrae 6-9 bearing ribs; dorsal-fin pterygiophores associated with Weberian complex (vertebrae 1-5) and vertebrae 6-11. Dorsal lamina of Weberian complex ornamented with series of three bony knobs. Parapophyses of fourth vertebra form broad lamina over swim bladder. Parapophysis of fifth vertebra long, curved anteriorly and extended laterally to body surface. Parapophyses of fourth and fifth vertebrae separated by deep notch ( Fig. 3 ). No horizontal bony lamina developed on precaudal, caudal or ural centra. Hemal spines simple, not bifid, on vertebrae articulating with anal-fin pterygiophores.

Color in alcohol. Pigmentation variable with two distinct color morphs, one dark ( Fig. 4 ) and one light. Dark morph with head light brown and irregularly mottled with darker pigment; overall body light brown with three poorly defined dark saddles, first beneath dorsal fin, and two more on posterior body. Individual unculiferous tubercles may be unpigmented or darkly pigmented giving speckled appearance to body. Ventral surface light brown with dark pigment concentrated in unculiferous tubercles. All fins and barbels mottled with dark pigment. Light morphs have similar pigmentation pattern to dark morphs but lack series of dark saddles on dorsal surface.

Size and sexual dimorphism. Specimens range from 19.5-30.0 mm SL. The largest specimens examined are females with ripening ova (0.5 mm in diameter). No observed dimorphism of body ornamentation, fins or pigmentation.

Distribution. Pseudobunocephalus lundbergi is currently known from just a few localities in the lower río Caura (type locality), upper río Apure, and río Meta ( Fig. 5 ), but is likely more widely distributed within the río Orinoco basin of Colombia and Venezuela.

Etymology. The specific name is patronymic in honor of Dr. John G. Lundberg of The Academy of Natural Sciences of Philadelphia. Lundberg served as the author’s Ph.D. advisor, and has made numerous contributions to the field of Neotropical ichthyology and the systematics of siluriform and gymnotiform fishes.

Figures

Fig. 4. Dorsal, lateral and ventral views of Pseudobunocephalus lundbergi, Holotype,ANSP 168817, 28.4 mm SL, Venezuela, Bolivar, caño Barranca, approximately 1.25 hours downstream from Jabillal (opposite bank) on río Caura (07°08’N 65°04’W), collected by J. Böhlke and W. Saul, 30 Jan 1977. Note the caudal fin is normal and intact, but has been creased and folded in preservation. Photographs by T. R. Vigliotta.

Fig. 3. Dorsal view of the neurocranium and Weberian complex of Pseudobunocephalus lundbergi, ANSP 172505. Arrow indicates the exit of the infraorbital canal from the sphenotic. Scale bar equals 1 mm.

Fig. 1. Lateral view (anterior to the right) of the suspensorium, hyoid arch and lower jaw of Pseudobunocephalus lundbergi, ANSP 172505, paratype. Scale bar equals 1 mm.

Fig. 5. Distribution map for Pseudobunocephalus lundbergi with the type locality indicated by a star symbol.