Pseudolaguvia tenebricosa, Britz, Ralf & Ferraris, Carl J., 2003

Britz, Ralf & Ferraris, Carl J., 2003, Myanmar (Teleostei: Ostariophysi: Siluriformes: Erethistidae), Zootaxa 388, pp. 1-8 : 2-5

Pseudolaguvia tenebricosa , new species

( Fig. 1 a­e, Table 1 )

Holotype: USNM 373293, 29.4 mm SL; Myanmar: Kayin Division: Pathe Chaung, hill stream, 13 miles east of Taungoo, 19°01'11"N, 96°35'33"E; 39 m above sea level; 18 March 2003, R. Britz, R. Roesler & Myo Nyunt.

Paratypes: USNM 374987, 14 specimens, 27.6–31.5 mm SL; same data as holotype; 9 May 2003, Tin Win, Ye Hein Htet, Aung Tun Zaw, and Tin Win Htwe.

Additional material: CAS 98614, 2 specimens, 28.7–30.4 mm SL; Myanmar: Kachin Division: Nan Kwe Chaung; 25°20.405' N 97°17.049'E; 138 m above sea level; 0 4 Nov. 1997, Carl J. Ferraris jr., U Tun Shwe & Mya Than Tun.

Diagnosis. Pseudolaguvia tenebricosa differs from P. tuberculata (fig. 2) (morphometric data calculated from Prashad & Mukerji's [1929] measurements) in having an adipose fin not reaching posterior insertion of dorsal fin (vs. adipose fin reaching dorsal fin), a narrower (23.8–25.1 vs. 26.7 % SL and 83.2–87.5 vs. 88.9 % HL) head, and a shorter snout (12.8–14.3 vs. 16.7 % SL and 44.7–50.6 vs. 55.6 % HL).

Description. Small species with a maximum length of 31.5 mm SL. Morphometric information for holotype and paratypes are provided in Table 1 .

Dorsal­fin rays II, 6; pectoral­fin rays I, 8; pelvic­fin rays i,5; anal­fin rays iii,7, with the first ray very small, splint­like. Principal caudal­fin rays i,7,7,i.

Head dorsoventrally depressed, with subterminal mouth and broad fleshy lips. Upper lip continuing into maxillary barbels, the bases of which are connected to the sides of the head through a broad roughly triangular skin flap. Four pairs of barbels: Maxillary barbels extending to the base of the pectorals, lateral mandibular barbels only slightly shorter, medial mandibular barbels half as long as outer mandibular barbels, nasal barbels, arising from the internarial septum, reaching only two thirds the distance from naris to eye. Eye very small. Side and top of head scattered with numerous small keratinized tubercles; keratinized areas on dorsal surface of head may form short or longer irregular longitudinal lines that extend onto supraoccipital process; well­developed superfically situated scapular and humeral processes. Numerous tubercles along body forming parallel irregular series, one of which forms a straight line of light colored tubercles and runs along level of horizontal septum. Fleshy bases of adipose and anal fin also with tubercles. Rayed portions of fins without tubercles.

Pectoral fin with strong spine bearing five to seven serrae on the inner face; outer face also serrate. Dorsal spine strong with weak serrae on posterior face.

Thorax and anterior portion of abdomen flattened ventrally with large adhesive organ, consisting of 14­18 longitudinal, partly merging skin folds arranged in an elongate area, 6­ 7 mm long and 3­4 mm wide, with a deep median groove. Folds extend anteriorly to isthmus, so that anterior border of adhesive organ forms a V, with its tip pointing rostrally.

Caudal fin deeply bifurcate with upper lobe in most specimens slightly longer than lober lobe; uppermost principal caudal ray extending as a short filament.

Coloration. Body brown to almost black, but underside of head and belly posteriorly of insertion of pelvic fin light beige with melanophores in median groove of adhesive organ and close to anal fin insertion. Two narrow lighter bands on side of body, one extending from posterior insertion of dorsal fin in a curve down to posterior insertion of pelvic fin, another from posterior base of adipose fin to posterior insertion of anal fin. Barbels annulated black and white. Pectoral fin with dark anterior basal area, an annulated anterior face of spine, and a distal band with hyaline tip. Dorsal fin dark brown except for light posterior seam. Pelvic fin mostly hyaline, with dark basal area and narrow dark streak subdistally. Adipose fin dark brown with lighter seam. Anal fin with dark base and narrow band that forms a half circle enclosing an almost round central hyaline area; distal parts of anal fin also hyaline. Caudal fin dark brown except for two central hyaline windows in dorsal and ventral lobes.

Etymology. From the Latin adjective tenebricosus alluding to the dark, gloomy coloration of this species.

culata calculated from the measurements provided by Prashad & Mukerji (1929).

Habitat. Pathe Chaung (fig. 3), a left bank tributary of the Sittang River, is a small hill stream, with fast running, clear water, a sandy bottom and numerous rocks and boulders. Aquatic vegetation was absent. Water temperature was 24°C, with a pH of 8.5 and a conductivity of 70 µS. All specimens were collected during the daytime. The holotype was caught with a seine among branches lying in the water, and the paratypes were collected with a battery operated electroshocker.

Figures

FIGURE 1. Pseudolaguvia tuberculata, reproduction of original figures from Prashad & Mukerji (1929), rotated 90 ° from original. a. lateral view; b dorsal view of anterior body; c ventral view of anterior body.

Tables

TABLE 1. Summary of morphometric data of the two species of Pseudolaguvia. Data for P. tuber­

SL	Pseudolaguvia tene­ bricosa, Holotype 29.4	Pseudolaguvia tene­ bricosa, Paratypes (n= 14) 26.3­31.5	m 28.5	r2 1.4	Pseudolaguvia tuberculata 30.0
in % SL
Head length	28.6	26.6­29.6	28.4	0.7	30.0
Head width	23.8	23.2­25.1	24.1	0.6	26.7
Head depth	13.6	12.5­14.6	13.6	0.6	15.0
Snout length	14.3	12.8­14.2	13.4	0.5	16.7
Predorsal length	43.5	41.4­44.8	43.0	0.9
Prepectoral length SL	23.5	20.6­23.0	22.1	0.8
Preanal length	71.4	67.3­70.7	69.3	1.4
Body depth	23.8	17.1­23.7	20.1	2.5	23.3
Caudal ped depth	11.2	8.5­11.5	10.1	0.8	10.0
Caudal ped. length	16.0	15.4­17.5	16.3	0.5	18.3
Dorsal fin length	13.6	12.6­14.3	13.3	0.6
Dorsal fin depth	19.5	13.7­19.7	16.9	1.8	20.0
Pelvic fin length	16.0	12.8­14.9	13.8	1.0	13.3
Pectoral fin depth	21.9	18.5­24.9	20.9	2.1	18.3
Anal fin length	15.2	12.5­14.6	13.7	0.7
Caudal fin length	29.3	25.4­30.4	27.4	1.8	26.7
in % head length
eye diameter	9.5	8.8­11.8	10.4	0.9	11.1
interorbital width	29.8	28.8­32.1	30.2	0.9	27.8
snout length	50.0	44.7­50.6	47.3	2.1	55.6
head depth	47.6	44.9­50.0	47.8	1.5	50.0
head width	83.2	82.5­87.5	84.7	1.8	88.9