Glyptothorax robustus ( Boeseman 1966 )

Ng, Heok Hee & Kottelat, Maurice, 2016, The Glyptothorax of Sundaland: a revisionary study (Teleostei: Sisoridae), Zootaxa 4188 (1), pp. 1-92 : 73-77

Glyptothorax robustus ( Boeseman 1966)

( Fig. 37 )

Sundagagata robusta Boeseman, 1966: 243 , Fig. 1 (type locality: near Bogor, Java). Glyptothorax robustus — Rachmatika, 2003: 60, Pl. 30.

Glyptothorax aff. platypogon — Jiang et al., 2011: 280.

Material examined. JAVA : RMNH 25264 (holotype), 64.8 mm SL; Jawa Barat: vicinity of Bogor. MZB 1313 (8), 32.9–61.3 mm SL ; Jawa Barat: Kabupaten Bogor , Cileungsi. MZB 1428 (1), 60.8 mm SL : MZB 1429 (1), 46.8 mm SL; Jawa Barat: Kabupaten Bogor, Cidurian River at Jasinga. MZB 6471 (12), 30.1–57.3 mm SL ; Jawa Barat: Cisadane River at Bogor. MZB 1311 (1), 54.1 mm SL ; Jawa Barat: Ciliwung River at Bogor. MZB 1309 (6), 45.6– 59.9 mm SL ; Jawa Barat: Kabupaten Bogor , Citeureup. MZB 1430 (1), 58.6 mm SL ; Jawa Barat: Kabupaten Bogor , Ciampea. ZRC 43877 (29 alc., 1 c&s), 40.8–59.9 mm SL ; Jawa Barat: Sungai Cisadane near Leuwiliang. CMK 8974 (1), 52.5 mm SL ; Jawa Barat: Sungai Ciliwung at Cilebut.

SUMATRA: MZB 2003 (1), 29.1 mm SL ; Lampung: Kabupaten Lampung Selatan, Kecamatan Pulau Panggung, Way Sangharus at Air Naningan.

Diagnosis. Glyptothorax robustus is distinguished from all Sundaic congeners in lacking (vs. having) a medial pit in the thoracic adhesive apparatus and having (vs. lacking) prominent dark longitudinal stripes running through each caudal-fin lobe. It further differs from G. platypogon , the only other congener known from Java, in having a straight (vs. convex) dorsoposterior margin of the adipose fin, a more slender caudal peduncle (6.6–8.3% SL vs.

8.0–11.4) and a longer caudal fin (26.5–30.4% SL vs. 20.1–27.0) with narrower lobes ( Fig. 30 ). The difference in the caudal peduncle depth between G. platypogon and G. robustus is more marked when compared to the body depth at anus (caudal peduncle depth 1.6–1.9 times in body depth at anus vs. 2.1–2.4 respectively). Glyptothorax robustus is further distinguished from the remaining Sundaic congeners in having the following unique combination of characters: premaxillary tooth band approximately half exposed when mouth is closed; eye diameter 7–10% HL; interorbital distance 28–33% HL; head length 23.6–29.3% SL; anteromedial striae in thoracic adhesive apparatus absent; pectoral-fin spine length 16.8–19.8% SL; predorsal length 36.7–40.0% SL; smooth posterior margin of dorsal-fin spine; margin of dorsal fin concave; dorsal-to-adipose distance 16.9–20.4% SL; straight dorsoposterior margin of adipose fin; prepelvic length 47.9–52.4% SL; body depth at anus 14.2–17.7% SL; post-adipose distance 17.0–19.6% SL; almost uniform body with diffuse pale patches and lacking (vs. having) dark vertical bars at the adipose-fin base and the base of the caudal fin.

Description. Morphometric data in Table 15 . Head depressed; body subcylindrical. Dorsal profile rising evenly from tip of snout to origin of dorsal fin, then sloping gently ventrally from origin of dorsal fin to end of caudal peduncle. Ventral profile straight to anal-fin base, then sloping gently dorsally from anal-fin base to end of caudal peduncle. Anus and urogenital openings located at vertical through middle of adpressed pelvic fin. Skin tuberculate, with tubercles of even size on sides of body. Lateral line complete and midlateral. Vertebrae 15+17=32 (3), 16+16=32 (1), 15+18=33 (1), 16+17=33 (4), 17+16=33 (2), 16+18=34 (2), 17+17=34 (6), 18+16=34 (2) or 18+17=35 (1).

Head depressed and broad, triangular when viewed laterally. Snout prominent. Anterior and posterior nares large and separated only by base of nasal barbel. Gill opening broad, extending from ventral margin of posttemporal to isthmus. First branchial arch with 2+5 (9), 2+6 (8) or 2+7 (3) rakers. Bony elements of dorsal surface of head covered with thick, tuberculate skin. Eye ovoid, horizontal axis longest; located entirely in dorsal half of head.

Barbels in four pairs. Maxillary barbel long and slender, extending to middle of pectoral-fin base. Nasal barbel slender, extending to midway between its base and anterior orbital margin. Inner mandibular-barbel extending to midway between its base and that of pectoral spine. Outer mandibular barbel extending to two-thirds of distance between its base and that of pectoral spine.

Mouth inferior, premaxillary tooth band partially (approximately half) exposed when mouth is closed. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary teeth appearing in single broad semilunate band. Dentary teeth in a single crescentic band, consisting of two separate halves tightly bound at midline.

Thoracic adhesive apparatus consisting of keratinized striae in an ovate field extending from isthmus to just beyond posterior limit of pectoral-fin base ( Fig. 3 o). Anteromedial striae and medial pit absent.

Dorsal fin located above anterior third of body, with I,6 (20) rays; fin margin concave; spine short and straight, smooth on anterior and posterior margins. Adipose fin with anterior margin straight or slightly concave and posterior margin straight. Caudal fin strongly forked, with lower lobe slightly longer than upper lobe and i,7,8,i (20) principal rays. Procurrent rays symmetrical and extending only slightly anterior to fin base. Anal-fin base vertically opposite adipose-fin base. Anal fin with straight anterior margin and straight or slightly concave posterior margin; with iv,7,i (1), iv,8 (2), iv,8,i (7), iv,9 (4), v,8 (1), iv,9,i (4) or iv,10,i (1) rays. Pelvic-fin origin at vertical through posterior limit of dorsal-fin base. Pelvic fin with slightly convex margin and i,5 (20) rays; tip of adpressed fin not reaching anal-fin origin. Pectoral fin with I,7 (3), I,7,i (16) or I,8 (1) rays; posterior fin margin slightly concave; anterior spine margin smooth, posterior margin with 7–10 serrations.

Coloration. In 70% ethanol: dorsal and lateral surfaces of head and body medium gray or grayish brown, fading to light gray or beige on ventral surfaces. A thin, light brown mid-dorsal stripe extending from base of last dorsal-fin ray to origin of adipose fin; stripe absent in some individuals. Laterosensory pores rimmed in beige, imparting appearance of a diffuse light brown or light gray midlateral line in some individuals. Dorsolateral surfaces of body above lateral line with elongate diffuse pale patch spanning entire length of body in some individuals. Dorsal and ventral surfaces of caudal peduncle slightly paler in some individuals. All fins with fin rays proximally gray to grayish brown, becoming hyaline more distally, and diffuse melanophores on fin membranes. Pectoral and pelvic fins with gray or grayish brown on base of fin rays and posterior two-thirds hyaline. Anal fin with gray or grayish brown base; gray or grayish brown spot on anterior third of fin present in some individuals. Adipose fin gray or grayish brown with hyaline distal margin. Each caudal-fin lobe with distinct gray or grayish brown longitudinal stripe on about half of outer fin rays; most of inner rays of lobes hyaline. Maxillary and nasal barbels gray or grayish brown dorsally, light brown or light gray ventrally. Mandibular barbels beige or light gray.

Habitat. Glyptothorax robustus is found syntopically with G. platypogon , and the reader is referred to the account for that species for information on its habitat.

Distribution. Glyptothorax robustus is known from river drainages in western Java (the Ciliwung and Cisadane river drainages) and the southern tip of Sumatra ( Fig. 26 ).

Comparisons. Glyptothorax robustus is further distinguished from G. amnestus in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus and having a more slender caudal peduncle (6.6–8.3% SL vs. 9.8–11.2), from G. decussatus in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus and having a more slender caudal peduncle (6.6–8.3% SL vs. 10.3–10.9), and from G. exodon in having the premaxillary tooth band approximately half (vs. almost entirely) exposed when the mouth is closed, a smaller eye (diameter 7–10% HL vs. 10–13) and a smaller dorsal-to-adipose distance (16.9–20.4% SL vs. 21.9–26.3). It further differs from G. famelicus in having a greater predorsal length (36.7–40.0% SL vs. 32.1–35.2), a longer pectoral-fin spine (16.8–19.8% SL vs. 14.0–15.6), a deeper body (depth at anus 14.2–17.7% SL vs. 11.4–14.3) and lacking (vs. having) a prominent pale midlateral stripe on the body, from G. f u s c u s in having narrower striae on the thoracic adhesive apparatus, a concave (vs. straight) dorsal margin of the dorsal fin and in lacking (vs. having) a chevronshaped area devoid of striae in the posterior third of the thoracic adhesive apparatus (compare Figs. 3 e and 3n). and from G. keluk in having a shorter pectoral-fin spine (16.8–19.6% SL vs. 19.4–22.9), a straight (vs. convex) dorsoposterior margin of the adipose fin, and a longer post-adipose distance (17.0–19.6% SL vs. 15.2–16.7).

Glyptothorax robustus is further distinguished from G. ketambe in having a longer pectoral-fin spine (16.8– 19.6% SL vs. 14.3–16.6), a greater predorsal length (36.7–40.0% SL vs. 33.3–35.9), a greater prepelvic length (47.9–52.4% SL vs. 45.4–47.8), a shorter dorsal-to-adipose distance (16.9–20.4% SL vs. 21.5–25.6), a shorter post-adipose distance (17.0–19.6% SL vs. 19.5–21.7) and lacking (vs. having) a prominent pale midlateral stripe on the body, from G. m a j o r in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus and having a more tapering body, as manifested by the larger ratio between the body and caudal peduncle depths (caudal peduncle depth 2.2–2.8 times in body depth at dorsal-fin origin vs. 1.7–2.4), and from G. nieuwenhuisi in having an almost uniform (vs. highly mottled) body with indistinct pale patches (vs. absent). It further differs from G. pictus in having a more slender caudal peduncle (depth 6.6–8.3% SL vs. 8.4–10.9) and lacking (vs. having) dark vertical bars at the adipose-fin base and the base of the caudal fin, from G. platypogonides in having a shorter dorsal-to-adipose distance (16.9–20.4% SL vs. 20.2–23.6), and from G. plectilis in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus and having a more slender caudal peduncle (depth 6.6–8.3% SL vs. 8.4–10.6). Glyptothorax robustus is further distinguished from G. prashadi in having a narrower head (17.6– 20.3% SL vs. 20.2–22.8), a concave (vs. straight) margin of the dorsal fin and a more slender caudal peduncle (6.6– 8.3% SL vs. 8.3–10.3), from G. schmidti in having a greater predorsal length (36.7–40.0% SL vs. 31.6–36.9), a shorter dorsal-to-adipose distance (16.9–20.4% SL vs. 23.9–28.1) and lacking (vs. having) a prominent pale midlateral stripe on the body, and from G. stibaros in having a shorter predorsal distance (36.7–40.0% SL vs. 39.1– 42.8) and a smooth (vs. serrated) posterior margin of the dorsal-fin spine.

Figures

FIGURE 1. Schematic illustration of thoracic adhesive apparatus of Glyptothorax, showing structures defined and mentioned in this study: anterolateral striae (ALS); anteromedial striae (AMS); medial pit (MP) (based on G. plectilis, MZB 4530, 50.2 mm SL).

FIGURE 3. Thoracic adhesive apparatus of: a. Glyptothorax amnestus, ZRC 54231, paratype, 51.2 mm SL; b. G. decussatus, MZB 17216, holotype, 74.5 mm SL; c. G. exodon, BMNH 1982.3. 29.190, paratype, 63.2 mm SL; d. G. famelicus, USNM 193015, holotype, 73.3 mm SL; e. G. f u s c u s, ZRC 42123, 54.3 mm SL; f. G. keluk, MZB 17217, holotype, 52.5 mm SL; g. G. ketambe, MZB 8694, holotype, 100.0 mm SL; h. G. major, ZRC 38761, 59.1 mm SL; i. G. nieuwenhuisi, MZB 16475, 61.0 mm SL; j. G. pictus, MZB 17218, holotype, 54.2 mm SL; k. G. platypogon, ZRC 48376, 56.3 mm SL; l. G. platypogonides, UF 166626, 52.4 mm SL; m. G. plectilis, ZRC 46420, paratype, 44.3 mm SL; n. G. prashadi, CMK 25369, 50.7 mm SL; o. G. robustus, ZRC 48377, 59.9 mm SL; p. G. schmidti, CMK 4536, 74.6 mm SL; q. G. stibaros, MZB 17215, holotype, 55.3 mm SL. Illustrations not to scale.

FIGURE 26. Map showing collection localities of Glyptothorax pictus, G. plectilis and G. robustus.

FIGURE 30. Lateral views of caudal region of: a. Glyptothorax platypogon, ZRC 43876, 51.0 mm SL; b. G. robustus, ZRC 43877, 59.9 mm SL. Illustrations not to scale.

FIGURE 37. Glyptothorax robustus, ZRC 48377, 59.9 mm SL; Java: Jawa Barat, Cisadane River. Dorsal, lateral and ventral views.

Tables

TABLE 15. Morphometric data for Glyptothorax robustus (n = 20).

	Range	Mean±SD
Standard length (mm)	40.8–59.9
%SL
Predorsal length	36.7–40.0	38.1±1.18
Preanal length	64.5–67.6	65.7±0.94
Prepelvic length	47.9–52.4	50.2±1.68
Prepectoral length	19.9–23.8	21.8±1.12
Length of dorsal-fin base	11.9–14.9	13.0±0.60
Dorsal-fin spine length	13.6–16.4	14.7±0.79
Length of anal-fin base	14.0–17.3	15.3±0.82
Pelvic-fin length	13.9–16.6	15.0±0.86
Pectoral-fin length	20.4–25.3	23.2±1.53
Pectoral-fin spine length	16.8–19.6	18.0±0.84
Caudal-fin length	26.5–30.4	28.7±1.21
Length of adipose-fin base	12.8–19.0	15.7±2.11
Dorsal to adipose distance	16.9–20.4	18.4±1.36
Post-adipose distance	17.0–19.6	18.1±0.86
Length of caudal peduncle	17.4–20.9	18.5±0.94
Depth of caudal peduncle	6.6–8.3	7.2±0.53
Body depth at anus	14.2–17.7	15.4±1.13
Body depth at dorsal-fin origin	20.0–23.6	21.8±1.20
Head length	23.6–29.3	26.9±1.57
Head width	17.6–20.3	19.2±0.94
Head depth	15.5–17.2	16.1±0.51
%HL
Snout length	44–49	47±1.5
Interorbital distance	28–33	29±1.8
Eye diameter	7–10	9±1.2
Nasal barbel length	13–23	19±3.3
Maxillary barbel length	82–108	95±9.1
Inner mandibular barbel length	29–40.	35±3.0
Outer mandibular barbel length	41–62	49±7.3