Garra robertsi , Thoni, Ryan J. & Mayden, Richard L., 2015
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Garra robertsi sp. nov.
( Fig. 1View FIGURE 1)
Holotype. FMNH 99403, 70.4 mm SL; Malaysia: Sabah: Kota Marudu, Marak Parak, Sungai Bongan River. Collected by R. B. Stuebing, October 1988.
Paratypes: FMNH 126067, 3 specimens; UF 237241View Materials, 1 specimen; same data as holotype.
Diagnosis. Garra robertsi is distinguished from its only other Bornean congener, G. borneensis ( Fig. 2View FIGURE 2), by the following characters: five (versus four) transverse scale rows above lateral line, first dorsal-fin ray extending beyond the posterior-most extent of any other part of the dorsal fin when depressed (versus not extending posteriorly beyond last ray when depressed), deeply embedded scales (versus exposed scales) on the breast, absence (versus presence) of a stark, contrasting black stripe on lower caudal-fin rays, two nearly continuous patches (versus 3 discrete patches) of tubercles on snout, absence (versus presence) of a lateral stripe, presence (versus absence) of broad suborbital bar, a thickened anteromedial fold on the lower lip, and fewer papillae extending onto the callous pad from the posterior flap of the lower lip.
Description. Morphometric and meristic data are provided in Tables 1 and 2, respectively. The general physical appearance and morphology of the species is presented in Figure 1View FIGURE 1. Body elongate; subcylindrical to triangular in cross-section anteriorly, becoming laterally compressed posteriorly, with the caudal peduncle width less than one half its depth. Snout sloping downward from nares to anterior-most point; small to large tubercles, depending on breeding condition and sex, on rostral and lateral lobes of snout. Shallow transverse groove present and proboscis absent; slight hump may be present immediately anterior to nares, hump becoming more prominent in larger individuals. Dorsal profile rises steadily to dorsal-fin origin; slightly convex. Dorsal profile from dorsalfin origin to caudal base sloping downward, without curvature, to a level equal with dorsal edge of orbit. Entire ventral surface flat except for a slight convex rise at caudal peduncle.
Head acute when viewed laterally; rounded from dorsal and ventral view. Head length (HL) about one fourth of standard length (SL). Head width roughly 2 / 3 HL. Orbit roughly 1 / 5 of HL. Mouth with mental disc; disc slightly less than 1 / 3 HL; disc roughly 2 / 3 as long as wide. Rostral cap with 22-27 fimbriae; posterior edge of cap folds at connection with lower lip, creating a lobe with papillae at the widest point of mental disc; lobe may not be homologous with anterolateral lobe of other Garra species. Rostral cap covers upper jaw, often leaving lower jaw visible. Two pairs of barbels; rostral barbels two to three times the length of maxillary barbels.
Tubercles erect; appearing to be present on both males and females, but are considerably more conspicuous in breeding males, occurring in two main patches with little delimitation between them. Rostral lobe with two parallel, horizontal rows of small tubercles; no more than 8 tubercles per row. Tubercles on lateral lobe in circular pattern and occurring immediately posterior and lateral to rostral lobe with only a small depression dividing the tuberculate areas. In the most tuberculate males, some individuals may have one or two small tubercles immediately posterior to nares.
Dorsal-fin origin slightly nearer to tip of snout than to caudal-fin base; margin of fin concave; first branched ray the longest, slightly longer than HL, and extending beyond any other part of the depressed; rays ii 8. Anal-fin origin beginning at vertical to posterior extent of depressed dorsal fin; fin length about 1 / 4 to 1 / 5 SL; rays i 5. Paired fins inserted horizontally. Pectoral fins slightly shorter than head length; rays i 13 (2 specimens), i 14 (12), i 15 (1). Pelvic fins nearly equal in length to pectoral fins. Pelvic-fin rays ii 7. Caudal fin forked; lobes roughly equal in length; total rays 19, branched rays 17.
Preserved coloration. Dorsum of head and body uniformly brown; body darker than head. Head light brown, transitioning to dark brown anterior to nares. Dark brown extending anteriorly to nares and grooves surrounding tubercle patches where dark brown to black lines encircle nares, and is present in grooves and snout. Side of head light brown. Broad, dark brown and anteroventrally angled suborbital bar present. Rostral lobe and dorsolateral surface of rostral flap brown. Maxillary and rostral barbels brown to near tips.
Dorsal scales dark brown with no distinct pattern. Lateral-line scales and first rows above and below lateral line brown and with distinct dark vertical bar in the posterior field. Bars on scales are very distinct to vertical near anal fin; scales posterior to vertical of anal-fin origin have distinct dark margins creating crosshatched pattern. Scales below horizontal to pectoral-fin insertion lightly pigmented to immaculate; venter of body around anal fin and caudal peduncle immaculate.
Dorsal-fin membranes with light pigmentation basally and distally. Distal third of fin with distinct dark and irregularly shaped streaks. Anal-fin rays with dark pigmentation along margins. First three anal fin membranes with melanophores along posterior margin of rays. Remaining rays immaculate except for medial dark pigmentation that together form medial band. Leading ray and first membranes of pelvic fin darkly pigmented from base to margin. Remaining rays lightly pigmented; membranes posterior to ray 5 with melanophores concentrated on basal 1 / 3. First five rays and membranes of pectoral fin dark with dense concentrations of melanophores; remaining rays and membranes as in posterior-most rays of pelvic fin. Caudal-fin rays and membranes lightly pigmented with no discernable bars or stripes; basal 1 / 3 of principal caudal ray and three lower-most branched rays may be more dusky than other rays and membranes.
TABLE 2. Frequency tables of meristic variables for Garra robertsi and G. borneensis . Values include the holotype for both species. Holotype condition for G. borneensis signified with *; Holotype condition for G. robertsi signified with +.
Etymology. This species epithet “ robertsi ” is in honor of Dr. Tyson Roberts, a prominent ichthyologist with a long-running focus on Bornean and Southeast Asian fishes.
Distribution. Garra robertsi is currently known to occur only in the Sungai Bongan and Tempassuk rivers in northern Sabah, Malaysia. Due to its occurrence in separate drainages, it is likely present in other rivers in the northern Borneo.
|upper caudal fin lobe length||32.3|
|lower caudal fin lobe length||31.2|
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