Paralaubuca harmandi Sauvage, 1883

Tangjitjaroen, Weerapongse, Randall, Zachary S., Yang, Lei, Grudpan, Chaiwut & Page, Lawrence M., 2025, Taxonomic revision of Paralaubuca (Cypriniformes, Xenocyprididae), a taxon seemingly in decline, Zootaxa 5647 (4), pp. 301-330 : 322-323

Paralaubuca harmandi Sauvage, 1883

( Figures 1 , 5 , 10 )

Paralaubuca Harmandi Sauvage, 1883:153 . Type locality: Thailand: Mé-Nam (Chao Phraya).

Holotype: MNHN A-6427.

Culter siamensis Hora, 1923:149 , pl. 10 fig. 1, pl. 11 figs. 4–5. Type locality: Thailand: Bangkok.

Holotype: ZSI F 10504 /1.

Culter wolfi Fowler, 1937:163 , fig. 101. Type locality: Thailand: Pitsanulok. Holotype: ANSP

68016.

Paralaubuca harmandi was described by Sauvage in 1883 based on a single specimen ( Figure 10A ) from the Chao Phraya River, Thailand having 7 branched dorsal-fin rays, 24 branched anal-fin rays, and 75 lateral-line scales. Bănărescu (1971) examined the holotype and noted it measured 147 mm SL .

Culter siamensis was described by Hora (1923) based on a single specimen measuring 175 mm SL ( Figure 10B ) from Bangkok, with 9 (=7 branched) dorsal-fin rays, 24 branched anal-fin rays, 13 pectoral-fin rays, and 75 lateral-line scales. Hora (1923) also gave a count of 7 pelvic-fin rays, which perhaps was an error or based on an aberrant specimen, given the otherwise consistent count of 9 pelvic-fin rays in Paralaubuca . We agree with Bănărescu (1971) that C. siamensis is a synonym of P. harmandi .

Culter wolfi was described by Fowler (1937) from the Chao Phraya basin at Pitsanulok, Thailand. The holotype ( Figure 10C ) measured 205 mm TL, and four paratypes measured 123–185 mm TL. The five specimens had 7 branched dorsal-fin rays, 14 pectoral-fin rays, 9 pelvic-fin rays, and 22–23 branched anal-fin rays. The lateral-line scale count was given as “23 to 25 (overlap 5 to 10, and sometimes auxiliary median series of 8 scales may be interposed) + 53 to 55 + 7 to 9 in lateral line.” We interpret this to mean lateral-line scales in a single row would number at least 73 and possibly as many as 84. Fowler noted C. wolfi was similar to C. siamensis but differed in having the pectoral fins longer than the head. Bănărescu (1971) examined the holotype and paratypes of C. wolfi , which he considered a synonym of P. harmandi , and other specimens he assigned to P. harmandi to describe the species as having 7 branched dorsal-fin rays, 21–25 branched anal-fin rays, 70–86 lateral-line scales, and 26–33 rakers on the first gill arch. We found the holotype has 80 and paratypes have 73–80 lateral-line scales and agree with Bănărescu (1971) that C. wolfi is a synonym of P. harmandi .

Diagnosis. Paralaubuca harmandi is distinguished from P. typus and P. barroni by having 70–87 vs. 68 or fewer lateral-line scales, usually 22–24 vs. 24–29 branched anal-fin rays, 26–33 (usually 28–32) vs. 20–28 (usually 26 or fewer) scales around caudal peduncle, and total vertebral counts of 41–42 (average=41.9, n=9) vs. 38–41 (average=39.3, n=21) in P. typus ; and 38–41 (average=39.9, n=7) in P. barroni . Paralaubuca harmandi has shorter anal fin and anal-fin base, and smaller eye than P. typus and P. barroni ( Table 9). It is further differentiated from P. typus by having 29–33 vs. 31–51 rakers on first gill arch. Paralaubuca harmandi is distinguished from P. typus and P. barroni osteologically as described above and as shown in Figure 5 . Reaching 265 mm SL, P. harmandi is much larger than both P. typus and P. barroni , which reach 152.5 and 115.0 mm SL, respectively.

Description. See description of genus.

Distribution. Paralaubuca harmandi is known from the Chao Phraya and Mae Klong River basins of Thailand, and the Mekong River basin of Cambodia and Thailand ( Figure 8B ). Observations and collections of the species have been in flowing water in moderate to large rivers. Paralaubuca harmandi occurs syntopically with P. typus , both species having been collected at six of the 13 localities documented for P. harmandi .

Based on specimens in institutional collections, P. harmandi is known to be widespread in the Chao Phraya basin, occurring as far north as the Ping River in Chiang Mai Province and south to Bangkok, but appears to be relatively uncommon. In the Mae Klong River basin, it was recorded in Kanchanaburi Province in 1963 ( Johnsen 1963) and in Ratchaburi Province ( UMMZ 195277 ) in 1964. The species may have been extirpated from the Mae Klong basin, perhaps because of the massive dams on the mainstem and on each of its primary tributaries, the Khwae Noi and Khwae Yai .

Several publications have implied P. harmandi is widespread in the Mekong River basin, but the only verified records known to us are from two localities, the Mun River near Ubon Ratchathani, Thailand (NIFI 00068, UF 249816, UMMZ 195744), and Prek Andor, Cambodia (MNHN-IC-1983-0170). Bănărescu (1971) indicated the distribution of P. harmandi as Menam [= Chao Phraya] and Mekong drainages in Thailand, but all specimens listed by him were from the Chao Phraya basin. Taki (1974) did not include P. harmandi among the four names he used for species of Paralaubuca from Laos. Rainboth (1996) mentioned P. harmandi as being in the lower Mekong but provided no locality records and included a drawing of Culter siamensis from Hora (1923), who described C. siamensis from Bangkok, drained by the Chao Phraya River. Kottelat (2001) reported P. harmandi from the Mekong of Cambodia, Laos, and Thailand, but provided no locality records, and the photo on page 67 purported to be of P. harmandi is a photo of P. typus or P. barroni . So et al. (2019) did not include P. harmandi in a field guide to fishes of Cambodia. Rainboth et al. (2012) included a photo of P. harmandi in a photographic atlas of fishes of the Mekong, but the specimen in the photo was noted as having been from Chainat, Thailand on the Chao Phraya River. Vidthayanon (2008) described the distribution of P. harmandi as middle to lower Mekong and Chao Phraya basins and included the same photo as that in Rainboth et al. (2012) from the Chao Phraya River. Panitvong (2022) reported P. harmandi from the Chao Phraya and Mekong River basins and included a photo of P. harmandi from Phitsanulok (personal communication) on the Chao Phraya River. Taki et al. (2021) noted that no specimens conforming to P. harmandi were found in the Mekong River basin in surveys spanning seven years. Paralaubuca harmandi has not been collected in the Mekong River basin since the 1960s and may be extirpated from the basin. If gone from the Mae Klong and Mekong River basins, the species occurs now only in the Chao Phraya River basin.

Figures

FIGURE 1. Paralaubuca typus, (A) live, UF 248615, 95.6 mm SL, Ping River, Kamphaeng Phet Province, Thailand, 8 Feb 2022. (B) preserved, UF 193797, female, 123.6 mm SL, and (C) preserved male, 116.1 mm SL, Ping River, Kamphaeng Phet Province, Thailand, 10 Feb 2024. Paralaubuca barroni, (D) preserved, UF 249886, 72.9 mm SL, Mekong River, Ubon Ratchathani Province, Thailand, 16 Jul 2005. Paralaubuca harmandi, (E) live, UF 248526, 126.1 mm SL, Chao Phraya River, Ayutthaya Province, Thailand, 21 Jun 2022.

FIGURE 5. Lateral skull computed tomography (CT) scans of (A) Paralaubuca typus, UF 170312, 84.9 mm SL, Mun River, Ubon Ratchathani Province, Thailand, 16 Nov 2007, (B) P. barroni, ANSP 179934, 54.2 mm SL, Ubon Ratchathani Province, Thailand, 10 Feb 2021, and (C) P. harmandi, UMMZ 195277, 128.2 mm SL, Ratchaburi Province, Thailand, 14 Nov 1964. Dentary in blue, premaxilla in green, maxilla in pink, orbitosphenoid in yellow, parasphenoid in grey, entopterygoid in orange, supraneural 5 in red, exoccipital and supraoccipital in purple. Asterisk indicates suspensorium window of Gosline (1975).

FIGURE 8. Distributions of species of Paralaubuca. (A) Paralaubuca barroni. ★ type locality of Chela barroni, locality for P. barroni in China is an approximation. (B) Paralaubuca harmandi. · type locality of Culter siamensis, ▲ type locality of Culter wolfi, locality for P. harmandi in Cambodia is an approximation. Type localities of P. harmandi (Chao Phraya River) and Pseudolaubuca lateralis (Cochinchine) are ambiguous and not plotted. (C) Paralaubuca typus. ★ type localities of P. typus and Culter riveroi, ◆ type locality of Chela stigmabrachium.

FIGURE 10. Primary types of Paralaubuca harmandi and synonyms. (A) Paralaubuca harmandi, holotype, MNHN A-6427, 147.0 mm SL, Chao Phraya River, Thailand. Photograph by Jonathan Pfliger. (B) Culter siamensis, holotype, ZSI F 10504/1, 175.0 mm SL, Bangkok, Thailand. Drawing from Hora (1923). (C) Culter wolfi, holotype, ANSP 68016, 168.4 mm SL, Pitsanulok, Thailand. Photograph by Jenna Hill.