Homaloptera

Randall, Zachary S. & Page, Lawrence M., 2015, On the paraphyly of Homaloptera (Teleostei: Balitoridae) and description of a new genus of hillstream loaches from the Western Ghats of India, Zootaxa 3926 (1), pp. 57-86 : 62-66

Homaloptera van Hasselt 1823

( Figures 2 , 3 A, 4D, 5A)

Homaloptera van Hasselt, 1823:133 (type species: Homaloptera ocellata van der Hoeven 1830, by subsequent monotypy in van der Hoeven, 1830:211). Gender feminine.

Helgia Vinciguerra, 1890:328 (type species: Homaloptera bilineata Blyth, 1860:172 , by subsequent designation by Jordan 1920:448). Gender feminine.

Remarks. Two species names were listed in Homaloptera by van Hasselt (1823), H. javanica and H. fasciata . Both lacked a description or figure and are unavailable (nomina nuda) ( Hora 1932; Kottelat 1987). The first species described and figured under Homaloptera was H. ocellata van der Hoeven 1830 (see Roberts 1993:24 for 1830 as publication date), making H. ocellata the type species of Homaloptera . Homaloptera bilineata Blyth 1860 was placed in the genus Helgia Vinciguerra 1890 and subsequently designated as the type species of Helgia by Jordan (1920). Helgia Vinciguerra 1890 is a synonym of Homaloptera van Hasselt 1823 ( Hora 1932; Kottelat 1998). Kottelat (1998) recognized Homaloptera ocellata van der Hoeven 1830, H. bilineata Blyth 1860 , H. orthogoniata Vaillant 1902 , and H. ogilviei Alfred 1967 as possibly forming a clade ( Homaloptera sensu stricto) based on the following characters: “unique color patterns (having in common reddish tints and similar dark markings on the head and the fins), a slightly compressed body, 56–65 lateral-line scales and the dorsal-fin origin situated in advance of the pelvic-fin origin.” Based on this diagnosis and an elongated head and a lateral-line scale count of 61–77, Tan & Ng (2005) treated this same clade as a subgenus of Homaloptera . With the availability of more data and analyses, the only character provided by Kottelat (1998) that seems to be apomorphic for Homaloptera (sensu stricto) is color pattern.

Diagnosis. Distinguishing characters are given in Table 4 and shown in Figures 2 , 3 A, 4D and 5A. Homaloptera is distinguished by the following combination of characters: reddish tints on fins in life ( Fig. 3 A); dorsal-fin origin anterior to pelvic-fin origin; 7–8½, 8½ (M) branched dorsal-fin rays; 7 branched pelvic-fin rays; forked caudal fin; keeled scales ( Fig. 4 D); 20–27 predorsal scales; 59–73 total lateral-line scales; no adipose keel on caudal peduncle; anus closer to anal-fin origin than to pelvic-fin insertion; large rostral cap; 2 thick rostral barbels in close proximity to each other; thick triangular upper lip ( Fig. 5 A); fleshy pad between lateral portions of lower lip ( Fig. 5 A); absence of central furrow at isthmus.

Species included. Homaloptera ocellata van der Hoeven 1830, H. bilineata Blyth 1860 , H. orthogoniata Vaillant 1902 , H. ogilviei Alfred 1967 , H. confuzona Kottelat 2000 , and H. parclitella Tan & Ng 2005 . The type localities for species of Homaloptera are shown in Figure 6 .

Comparison. Homaloptera is distinguished from Homalopteroides by presence vs. absence of reddish tints on fins in life, having a dorsal-fin origin anterior vs. posterior to pelvic-fin origin; 7–8½, 8½ (M) vs. 6–8½, 7½ (M) branched dorsal-fin rays; 59–73 vs. 33–52 total lateral-line scales; large vs. small rostral cap; medial- and lateralrostral barbels in close proximity to one another vs. widely separated from one another at base; triangular vs. crescentic upper lip; thick vs. thin upper lip; presence vs. absence of pad between lateral portions of lower lip; and absence vs. presence of a central furrow at isthmus.

Homaloptera is distinguished from Homalopterula by presence of reddish tints on fins in life vs. without red color; dorsal-fin origin anterior vs. posterior to pelvic-fin origin; 7–8½, 8½ (M) vs. 5½ and 7½, 7½ (M) branched dorsal-fin rays; keeled vs. smooth scales; 20–27 vs. 28–56 predorsal scales; forked vs. truncated or deeply emarginated caudal fin; absence vs. presence of adipose keel on caudal peduncle; large vs. small rostral cap; medial- and lateral-rostral barbels in close proximity vs. widely separated at base; triangular vs. crescentic upper lip; presence of fleshy pad vs. lobes between lateral portions of lower lip; and absence vs. presence of a central furrow at isthmus.

Homaloptera is distinguished from Balitoropsis and Pseudohomaloptera by presence vs. absence of reddish tints on fins in life; 7 vs. 8–9 branched pelvic-fin rays; 20–27 vs. 13–15 and 13–19 predorsal scales, respectively. It is further distinguished from Balitoropsis by having 59–73 vs. 42–55 total lateral-line scales; anus closer to anal-fin origin vs. closer to pelvic-fin insertion; triangular vs. crescentic upper lip.

Material examined. Homaloptera ocellata : Java: RMNH 2723 (holotype); ZMA 100.645 (2), 103.205 (1). Sumatra: UF 161605 (1), 161719 (4), 161718 (2), 166096 (4), 166104 (2), 166106 (2), 166107 (4). H. bilineata : Myanmar: RMNH 10263 (1); CAS 231723 (4). H. orthogoniata: Borneo (Kalimantan) : RMNH 7790 (lectotype); CAS 49326 (1). H. ogilviei: Peninsular Malaysia: ZRC 1555 (holotype); BMNH 1966.9.26.1 (paratype); RMNH 25443 (paratype); UF 235405 (1), 235408 (1). Sumatra: UF 161716 (2), 166085 (2), 166091 (2). Thailand: INHS 93605 (1). H. confuzona : Thailand: UF 169906 (1); INHS 93493 (5). H. parclitella: Peninsular Malaysia: ZRC 49257 (holotype); CAS-SU 39390 (2).

Figures

FIGURE 2. Dorsal, lateral, and ventral views of preserved Homaloptera ocellata, UF 161718, 64.1 mm SL, Way Seputhi, Lampung Province, Sumatra, Indonesia.

FIGURE 3. Lateral views of living (A) Homaloptera orthogoniata, not cataloged, Kalimantan, Borneo, Indonesia. Strong reddish tints on body likely breeding colors; (B) Homalopteroides smithi, UF 235740, 45.0 mm SL, Khlong Tasae, Salui Subdistrict, Chumphon, Thailand; (C) Homalopterula cf. ripleyi, not cataloged, Sumatra, Indonesia; (D) Balitoropsis zollingeri, not cataloged, Kalimantan, Borneo, Indonesia; (E) Pseudohomaloptera leonardi, UF 235735, 34.2 mm SL, Ta Pi River, Nakhon Si Thammarat, Thailand. Photos (A) & (D) by Renny Hadiaty. Photo (C) by Daniel Lumbantobing. Specimens not to scale.

FIGURE 4. Scale sizes and keel patterns of predorsal region: Large, and keeled scales, (A) Balitoropsis zollingeri, UF 166094, 52.1 mm SL; (B) Pseudohomaloptera tatereganii, RMNH 7632 (holotype), 64.6 mm SL. Large, and wart-like / keeled scales (C) Homalopteroides wassinkii, UF 183330, 43.6 mm SL. Medium, and keeled scales, (D) Homaloptera cf. ocellata, UF 161718, 64.1 mm SL. Small, and smooth scales, (E) Homalopterula ripleyi, ANSP 188908, 43.1 mm SL; (F) Ghatsa montana, CAS-SU 39871 (holotype), 46.6 mm SL. Scale bar represents 1 mm. Left side of photo is anterior.

FIGURE 5. Oral morphology of (A) Homaloptera cf. ocellata, UF 161718, 64.1 mm SL; (B) Homalopteroides wassinkii, UMMZ 155660, 46.2 mm SL; (C) Homalopterula ripleyi, ANSP 188908, 43.1 mm SL; (D) Balitoropsis zollingeri, UF 166094, 52.1 mm SL; (E) Pseudohomaloptera tatereganii, RMNH 7632 (holotype), 64.6 mm SL; (F) Ghatsa montana, (holotype) CAS- SU 39871, 46.4 mm SL. Abbreviations: CF, central furrow; FL, fleshy lobe; FP, fleshy pad; LJ, lower jaw; LL, lower lip; LRB, lateral-rostral barbel; MB, maxillary barbel; MRB, medial-rostral barbel; RC, rostral cap; UJ, upper jaw; UL, upper lip.

FIGURE 6. Type localities for species of Homaloptera. Asterisk represents the type species of the genus.

Tables

TABLE 4. Characters distinguishing Homaloptera, Homalopteroides, Homalopterula, Balitoropsis, Pseudohomaloptera and Ghatsa. Values are given as ranges; numbers in parentheses represent modal values. For Ghatsa, data from original descriptions are included; values in parentheses are for G. montana (CAS-SU 39871).

Character	Homaloptera	Homalopteroides Homalopterula	Balitoropsis	Pseudohomaloptera	Ghatsa ( G. montana )
No. specimens examined	51	148 24	42	37	1
Reddish tints on fins in life	Yes	No No	No	No	?