Molecular data from samples encompassing 22 nominal species of Poropuntius indicate that the species-level diversity in the genus has been vastly overestimated, likely due to inadequate taxon and geographic sampling and reliance on morphological characters that vary intra-specifically. The latter includes discrete mouth morphologies related to alternate feeding strategies (ecomorphs) within populations. One new species is described, Poropuntius anlaoensis Hoàng, Phạm & Trần, sp. nov., and 17 synonyms of six valid species names of Poropuntius, P. krempfi, P. alloiopleurus, P. huangchuchieni, P. laoensis, P. kontumensis, and P. deauratus, are recognised. Additional taxonomic changes in this widespread and generally poorly known genus are likely as more molecular and morphological data become available.

Cypriniformes, molecular systematics, phylogeny, Poropuntius anlaoensis sp. nov.

Thirty-three names currently are recognised as valid for species of Poropuntius (Fricke et al. 2023) with distribution of the genus ranging from the Irrawaddy River basin in Myanmar to the Mekong and Red River basins in Yunnan, China and south through Vietnam, Laos, Cambodia, Thailand, and peninsular Malaysia to Sumatra, Indonesia. The greatest diversity occurs in the Mekong basin of Yunnan and Vietnam, and only one species is known from peninsular Malaysia and one from Sumatra (Fricke et al. 2023).

Poropuntius has been characterised as usually having 8½ branched dorsal rays, large serrae on the posterior edge of the last simple dorsal ray, and tubercles covering the tip of the snout and occurring on the lacrimal bones (Rainboth 1996; Roberts 1998). Tubercles occur on both sexes and, at least in most species, on juveniles as well as adults (Roberts 1998). In addition, most species have rostral and maxillary barbels, a black to dusky submarginal stripe on the upper and lower caudal-fin lobes, and a well-developed keratinised edge on the lower jaw.

Considerable confusion surrounds the taxonomy of Poropuntius, with most species having been diagnosed using morphological characters that tend to be highly plastic and comparisons made to few congenerics. Wu et al. (2013) and Muhammad-Rasul et al. (2018) investigated molecular diversity of Poropuntius and, although they targeted only a few species and small geographic areas, their results suggested some morphological hypotheses concerning species delimitations are incorrect, and larger molecular studies are needed to improve our understanding of species diversity in Poropuntius. Recent fieldwork throughout much of the distribution of Poropuntius, especially in species-rich Vietnam, has provided material for a broader study of molecular variation in the genus. Results of that study, reported herein, suggest that several species names, including nominal species of Acrossocheilus and Hypsibarbus in Vietnam, are synonyms of previously described species. A newly discovered species from Vietnam is described using morphological and molecular characteristics.

The ML trees for the COI and Cytb sequences are shown in Fig. 2. The COI topology is consistent with recognition of 16 species (Fig. 2A), all represented by more than one sequence with ≥ 83% bootstrap support, including one undescribed species.

Figure 2. 

Maximum-likelihood tree based on (A) COI and (B) Cytb mitochondrial gene sequences for species of Poropuntius. Numbers on branches are ML bootstrap values (values > 50% shown). Bold sample labels are sequences from type localities. Blue sample labels in the Cytb tree are sequences from Wu et al. (2013). Colours of clades correspond to the freshwater ecoregions in Fig. 1.

The Cytb sequences were used to examine the results of the study of P. huangchuchieni in southwest China by Wu et al. (2013) with a greater Cytb dataset (Fig. 2B). The five major lineages identified by Wu et al. (2013) are reassigned. The LX lineage of Wu et al. (2013) from the Song Hong aligned with P. krempfi in our sequences, the SW of the Upper Salween with P. opisthopterus, the RL of the Song Hong with P. alloiopleurus, the MK-A of the Lower Lancang with P. huangchuchieni, and the MK-B of the Lower Lancang with P. laoensis. The greatest similarity in the Cytb sequences was 98% (±0.00), found between P. laoensis, which occurs in the Lower Lancang, Kratie – Stung Treng, northern Annam, Chao Phraya, and Middle & Lower Salween ecoregions, and P. huangchuchieni in the Lower Lancang (Table 1). The COI data for P. huangchuchieni (Fig. 2A) aligned with the reassignments based on the Cytb data and are not discussed further.

Seven of the 16 species recognised with COI data (Fig. 2A) include representatives of other nominal species now to be recognised as synonyms. One, the P. krempfi clade includes 12 specimens of three nominal species currently assigned to two genera: P. krempfi, Hypsibarbus annamensis, and H. macrosquamatus. The newly collected specimens of all three nominal taxa were collected from their type localities in the Song Hong and northern Annam ecoregions and are embedded with P. krempfi specimens from the Song Hong with a mean similarity of 98.8% (± 0.29) (Fig. 2A). This clade received 83% bootstrap support. Hypsibarbus annamensis, and H. macrosquamatus are synonyms of P. krempfi. The P. krempfi lineage in the Song Hong ecoregion has a COI sequence similarity of 97% (± 1.00) with P. alloiopleurus from the Song Hong, P. opisthopterus from the Upper Salween, P. burtoni from the Sittang - Irrawaddy, and P. schanicus from the Inle Lake, Myanmar (Table 2).

The P. alloiopleurus clade (Fig. 2A, B) consists of 13 specimens of six nominal species (plus specimens labelled P. huangchuchieni in Wu et al. (2013) and Zheng et al. (2016)), currently in two genera: P. alloiopleurus, P. baolacensis, P. brevispinus, P. rhomboides, Acrossocheilus macrophthalmus, and A. xamensis collected in the Song Hong and northern Annam ecoregions from their type drainages (Fig. 2A). The newly collected specimens are embedded with P. alloiopleurus specimens from the Song Hong and show a mean similarity of 99.5% (± 0.20). This clade receives 100% bootstrap support. Thus, we conclude that P. baolacensis, P. brevispinus, P. rhomboides, A. macrophthalmus and A. xamensis are synonyms of P. alloiopleurus. The P. alloiopleurus lineage observed in the Song Hong ecoregion has a COI sequence similarity of 97% (±1.00) with P. krempfi from the Song Hong, P. huangchuchieni and P. laoensis from the Lower Lancang, and P. opisthopterus from the Upper Salween (Table 2).

The P. huangchuchieni clade consists of three specimens of two nominal species, P. huangchuchieni and P. angustus collected from their type drainages in the Lower Lancang ecoregion. These specimens have a mean similarity of 100% (± 0.00) (Fig. 2A). Poropuntius angustus is a synonym of P. huangchuchieni. The P. huangchuchieni lineage in the Lower Lancang ecoregion has a COI sequence similarity of 97% (± 1.00) with P. laoensis from the Lower Lancang, P. alloiopleurus from the Song Hong, and P. opisthopterus from the Upper Salween (Table 2).

The P. laoensis clade consists of 17 specimens of three nominal species, P. laoensis, P. aluoiensis, and P. bantamensis collected in the Lower Lancang, Kratie – Stung Treng, northern Annam, Chao Phraya, and Middle & Lower Salween ecoregions including from their type localities. The newly collected specimens are embedded with P. laoensis specimens from the Kratie – Stung Treng and show a mean similarity of 99.1% (± 0.23) (Fig. 2A). This clade receives 97% bootstrap support. Poropuntius aluoiensis and P. bantamensis are synonyms of P. laoensis. The P. laoensis lineage observed in the Lower Lancang, Kratie – Stung Treng, northern Annam, Chao Phraya, and Middle & Lower Salween ecoregions has a COI sequence similarity of 97% (± 1.00) with P. huangchuchieni from the Lower Lancang, P. alloiopleurus from the Song Hong, and P. opisthopterus from the Upper Salween (Table 2).

The P. anlaoensis sp. nov. lineage consists of four specimens of a new species of Poropuntius. This lineage from the Annam ecoregion has its greatest COI sequence similarity of 94% (± 1.00) with P. kontumensis from the Kratie – Stung Treng (Table 2).

The P. kontumensis clade consists of six specimens of two nominal species, P. kontumensis and P. yalyensis, collected in the Kratie – Stung Treng ecoregion from their type localities. The newly collected specimens are embedded with P. kontumensis specimens from the type locality and have a similarity of 100% (± 0.00) (Fig. 2A). Poropuntius yalyensis is a synonym of P. kontumensis. The P. kontumensis lineage from the Kratie – Stung Treng ecoregion is most similar to P. carinatus from the Lower Lancang with a COI sequence similarity of 97% (± 1.00) (Table 2).

The P. deauratus clade consists of 57 specimens of six nominal species, P. normani, P. deauratus, P. bolovenensis, P. lobocheiloides, P. smedleyi, and P. solitus, collected the eastern Gulf of Thailand drainages, Malay Peninsula, Mekong Delta, Kratie – Stung Treng, Khorat Plateau, and Annam ecoregions, including from their type localities. These specimens are embedded with P. deauratus specimens from the Annam ecoregion and have a mean similarity of 98.7% (± 0.25). This clade receives 98% bootstrap support. Poropuntius normani, P. bolovenensis, P. lobocheiloides, P. smedleyi, and P. solitus are synonyms of P. deauratus. The P. deauratus lineage in the Eastern Gulf of Thailand drainages, Malay Peninsula, Mekong Delta, Kratie – Stung Treng, Khorat Plateau, and Annam ecoregions has a COI sequence similarity of 96% (± 1.00) with P. carinatus from the Lower Lancang and P. kontumensis from the Kratie – Stung Treng ecoregion (Table 2).

Taxonomic account

Cypriniformes

Cyprinidae Rafinesque, 1815

Poropuntini Menon, 1999

Poropuntius Smith, 1931

 Poropuntius krempfi (Pellegrin & Chevey, 1934)

Barbus (Lissochilichthys) krempfi Pellegrin & Chevey, 1934: 339. Type locality: Vietnam, Tonkin, Ngoi-Thia River at Nghia Lô, tributary of Red River upstream of Yên Bay. Holotype: MNHN 1934-0262.

Barbus (Puntius) annamensis Pellegrin & Chevey, 1936: 225, fig. 3. Type locality: Vietnam, Annam, Quảng Nam, Hàn Giang. Holotype: MNHN 1935-0337.

Lissochilus macrosquamatus Mai, 1978: 99, fig. 42. Type locality: northern Vietnam. Syntypes: DVZUT.

Notes

Specimens of Poropuntius krempfi (Fig. 3A, B) were recovered in a clade including topotypic material of Barbus annamensis and Lissochilus macrosquamatus. The clade was sister to a large clade including P. alloiopleurus, P. heterolepidotus, P. huangchuchieni, P. laoensis, and P. opisthopterus (Fig. 2A).

Figure 3. 

Species of Poropuntius. Poropuntius krempfi from A Song Hong ecoregion, UNS 2018-1410 B northern Annam, UNS 2018-2702; P. alloiopleurus from C Song Hong, UNS 2018-3010; P. laoensis from D upper Sekong’s tributary, UNS 2018-0404 E upper Sekong’s pool, UNS 2018-0304; P. huangchuchieni from F Lower Lancang, UNS 2018-0711. All photographed in life. Scale bars: 10 mm.

Specimens of P. krempfi from northern Annam (MNHN 1935:0337, MNHN 1969:42) were assigned by Rainboth (1996) to Hypsibarbus annamensis presumably due to the presence of a few tiny tubercles on the tip of the snout, but this trait is not useful for separating all species of the two genera. Some of our 41 specimens of P. krempfi have tiny tubercles on the tip of the snout. Rainboth (1996) noted that this species was unusual in being the only species of Hypsibarbus on the coastal side of the Annam Cordillera and in having a much longer dorsal spine with 26–28 serrations, compared to 20 or fewer in other species in the Mekong River drainage.

Hypsibarbus macrosquamatus from Song Hong, northern Vietnam (type: DVZUT) described by Mai (1978) and treated as Acrossocheilus macrosquamatus by Nguyễn and Ngô (2001) resembles our P. krempfi specimens from northern Annam with a lateral-line scale count of 29–33.

Distribution

Poropuntius krempfi is found in the Song Hong and northern Annam ecoregions.

 Poropuntius alloiopleurus (Vaillant, 1893)

Barbus alloiopleurus Vaillant, 1893: 201. Type locality: Vietnam, Tonkin, Black River. Holotype: MNHN 1892-0261.

Barbodes (Barbodes) huangchuchieni rhomboides Wu & Lin, in Wu et al. 1977: 248, pl. 7–8. Type locality: China, Yunnan, Yuanjiang River. Syntypes (15): KIZ 645614-15, 645617-19, 645622, 645624, 6440093, 6440392, 6440461, 6440564, 6450172, 6450191, 6450207, 6450322.

Poropuntius baolacensis (Nguyen, in Nguyễn and Ngô 2001): 387, fig. 189. Type locality: Vietnam, Cao Bang Province, Nho Que, Bao Lac [22°56'60"N, 105°40'00"E], Song Hong River drainage. Holotype: VNCNTTS H.01.72.13.01.

Poropuntius brevispinus (Nguyễn & Đoàn, 1969):12, fig. 7. Type locality: Vietnam, Hoa Binh Province, Suoi Rut stream. Syntypes (3): NCNTTSI H.01.72.10.01-03.

Acrossocheilus macrophthalmus Nguyen, in Nguyễn and Ngô 2001: 390, fig. 191. Type locality: Vietnam, Hoa Binh Province, Da Bac District, Da River at Thac Bo. Holotype: NCNTTSI H.01.72.14.01.

Acrossocheilus xamensis Kottelat, 2000: 38, fig. 1. Type locality: Laos, Houaphan Province, Houay Tangoua, small stream entering Nam Xam in Ban Houay Tangoua, 20°09'24"N, 104°32'50"E. Holotype: ZRC 45297.

Notes

Specimens of Poropuntius alloiopleurus (Fig. 3C) were recovered in a clade including topotypic material of Acrossocheilus macrophthalmus, A. xamensis, Barbodes huangchuchieni rhomboides, Poropuntius baolacensis, and P. brevispinus and was sister to a clade including P. heterolepidotus, P. huangchuchieni, and P. laoensis (Fig. 2A).

Kottelat (2000) noted that Acrossocheilus xamensis resembles Poropuntius but lacks the branched lateral-line canals diagnostic of Poropuntius. Our 12 specimens of P. alloiopleurus are missing branched lateral-line canals; branched canals are variable within Poropuntius and do not distinguish Poropuntius from Acrossocheilus. A paratype of A. xamensis exhibits the typical caudal-fin characteristic of Poropuntius, a dark marginal stripe along the lower lobe (Kottelat 2000, fig. 1).

According to Nguyễn (2001), A. macrophthalmus resembles P. alloiopleurus but has an eye diameter longer than the snout. Our 12 specimens of P. alloiopleurus have eye diameters that are shorter or longer than the snout.

Nguyễn and Ngô (2001) distinguished P. baolacensis from P. brevispinus in having 28–30 vs 18–22 serrae along the posterior margin of the last simple dorsal-fin ray. Our 12 specimens of P. alloiopleurus have 20–29 serrae on the last dorsal-fin ray, partially overlapping the serrae counts given to distinguish P. baolacensis and P. brevispinus.

Distribution

Poropuntius alloiopleurus is found in the Song Hong ecoregion.

 Poropuntius huangchuchieni (Tchang, 1962)

Barbus huangchuchieni Tchang, 1962: 96, fig. 1. Type locality: China, Yunnan, Hsi-Shuan- Pan-Na [Xishuangbanna]; Syntypes: ASIZB [now NZMC] 39256(1), 39865(1).

Poropuntius angustus Kottelat, 2000: 46, fig. 14. Type locality: Laos, Louangphabang Province, Houay Houn, ca. 3 km upstream of Ban Houay Lek, approx. 20°32'32"N, 102°40'51"E. Holotype: ZRC 45308.

Notes

In the original description of P. angustus, Kottelat (2000) made no specific mention of P. huangchuchieni. Topotypic material (UNS 2018-07-11, Fig. 3F) from the Nam Nứa, Lower Lancang ecoregion, in the upper reach of Nam Ou, the type locality of P. angustus, was genetically identical to that of P. huangchuchieni from the Lancang Jiang in Yunnan.

Distribution

Poropuntius huangchuchieni is found in the Lower Lancang ecoregion.

 Poropuntius laoensis (Günther, 1868)

Barbus laoensis Günther, 1868: 115. Type locality: Laos Moutains, Cochinchina. Holotype: BMNH 1862.7.28.15.

Poropuntius bantamensis (Rendahl, 1920): 1, fig. 1. Type locality: Thailand, Ban Tam, east of Doi Chieng Dao, pond fed by a subterranean stream. Holotype: NRM 10969.

Poropuntius aluoiensis (Nguyen, 1997): 1, fig. 1. Type locality: Vietnam, Thua Thien Hue Province, A Luoi District, A Sap stream at Nham, Sekong basin, 16°15'32"N, 107°13'31"E. Holotype: HNUE V1.1.21.

Notes

Our seven specimens of P. laoensis specimens (Fig. 3D, E) were collected in the upper Xekong drainage of Central Vietnam, the type locality, i.e., in the Lao Mountains of Cochin-China, now Central Vietnam. Topotypic material of P. bantamensis and P. aluoiensis resembled P. laoensis in having the proximal half of the caudal fin orange and the distal half bright yellow, and bold black submarginal stripes on the caudal fin.

Distribution

Poropuntius laoensis occurs in the Lower Salween, Chao Phraya, Lower Lancang, northern Annam, and Kratie-Stung Treng ecoregions.

 Poropuntius kontumensis (Chevey, 1934)

Cyclocheilichthys kontumensis Chevey, 1934: 32, fig. 1. Type locality: Vietnam, Annam, Pleiku Province, Kontum Lake [Mekong River drainage]. Types unknown.

Acrossocheilus yalyensis Nguyễn, in Nguyễn and Ngô 2001: 393, fig. 193. Type locality: Vietnam, Kon Tum Province, Sông Sesan [river]. Holotype: NCNTTSI H.01.72.15.01.

Notes

The five specimens of Poropuntius kontumensis (Fig. 4A) and Acrossocheilus yalyensis were collected in the Kratie – Stung Treng ecoregion from their type localities and were genetically identical.

Figure 4. 

Poropuntius kontumensis and P. deauratus. Poropuntius kontumensis from A Kratie–Stung Treng ecoregion (the Sesan drainage), UNS 2018-2201; P. deauratus from B northern Annam, UNS 2017-0310 C northern Annam, UNS 2018-2502 D southern Annam, UNS 2018-0801 E Mekong Delta (the Đồng Nai drainage) UNS 2017-1612 F Khorat Plateau (Sepon drainage), UNS 2018-0904 G upper Srepok drainage, UNS 2015-2301 H lower Srepok drainage’s pool, UNS 2015-3006. All photographed in life. Scales bars: 10 mm.

Distribution

Poropuntius kontumensis occurs in the Kratie-Stung Treng ecoregion.

 Poropuntius deauratus (Valenciennes, in Cuvier & Valenciennes, 1842)

Barbus deauratus Valenciennes, in Cuvier and Valenciennes 1842: 188. Type locality: Vietnam, Cochinchina [South of Hué; Kottelat 2000: 45]. Holotype: MNHN 2727.

Poropuntius normani Smith, 1931: 15. Type locality: Thailand, Chantaburi Province, Nam Tok Pliu, Kao Sabap, near Chantaburi. Holotype: USNM 90297.

Poropuntius smedleyi de Beaufort, 1933: 44. Type locality: Malaysia, Johor. Syntypes: ZRC [1, missing], ZMA 101.007 [Nijssen et al. 1993: 214).

Poropuntius bolovenensis Roberts, 1998: 124, fig. 5. Type locality: Laos, Champasak Province, Bolavens Plateau, Sekong basin, Xe Nam Noi, 300 m downstream from primary dam site of Xe Nam Noi–Xe Pian hydropower scheme. Lectotype: CAS 94251 [designated by Kottelat 2000: 46].

Poropuntius lobocheiloides Kottelat, 2000: 48. Type locality: Laos, Champasak Province, Bolavens Plateau, Xe Nam Noi 300 m downstream from primary dam site for Xe Nam Noi–Xe Pian hydropower scheme, Bolavens Plateau, Sekong watershed. Holotype: CAS 94257.

Poropuntius solitus Kottelat, 2000: 48, fig. 15. Type locality: Laos, Champasak Province, Bolavens Plateau, Huay Makchan-Gnai (Xe Nam Noy basin), south of Ban Taot at turnoff to Xe Nam Noy Project, on road from Pakse to Attapu, 15°04'14"N, 106°32'33"E. Holotype: ZRC 45310.

Poropuntius consternans Kottelat, 2000: 48. Type locality: Laos, Champasak Province, Bolavens Plateau, Sekong drainage, Xe Nam Noi, 300 m downstream from primary dam site of Xe Nam Noi–Xe Pian hydropower scheme, Bolavens Plateau, Sekong watershed. Holotype: CAS 94255.

Notes

The P. deauratus clade contained 56 specimens of six nominal species, P. normani, P. deauratus, P. bolovenensis, P. lobocheiloides, P. smedleyi, and P. solitus, collected from a wide area including the Eastern Gulf of Thailand drainages, Malay Peninsula, Mekong Delta, Kratie – Stung Treng, Khorat Plateau, and Annam ecoregions, including type localities.

Molecular data from specimens originally identified as P. bolovenensis, P. lobocheiloides, and P. solitus (GenBank: Song et al. 2017) are from specimens identified morphologically by Kang et al. (2016), who also discussed variation in these forms and in P. consternans. Kang et al. (2016) considered all to be P. bolovenensis. Our results agree with the conspecificity demonstrated by Kang et al. (2016) but place P. bolovenensis in the synonymy of P. deauratus. Roberts (1998) had correctly treated P. consternans and P. lobocheiloides, later named by Kottelat (2000), as ecomorphs of P. bolovenensis. Our five specimens of P. normani were collected in the same small area as the type locality.

Poropuntius deauratus occurs over a large geographic area and shows considerable variation in shape and color (Fig. 4B–H) as well as in the structural traits related to feeding morphology.

Distribution

Poropuntius deauratus is found in the Western Malaysia, Malay Peninsula Eastern Slope, Eastern Gulf of Thailand, Mekong Delta, Kratie-Stung Treng, Khorat, northern Annam, and southern Annam ecoregions.

 Poropuntius anlaoensis Hoàng, Phạm & Trần, sp. nov.

https://zoobank.org/17935DFC-446B-4F5C-AF44-4719D31BAD3C

Material examined

Holotype : UNS00762, 139.46 mm SL, female; An Lão drainage, Bình Định Province, Vietnam (14°40'30.6"N, 108°54'13.4"E, 547 m), 19 January 2013, Hoàng Đức Huy, Phạm Mạnh Hùng and Trần Trọng Ngân (Fig. 5). Paratypes: An Lão drainage, Bình Định Province, Vietnam (14°40'30.6"N, 108°54'13.4"E): UNS 2013-19-01, 5 specimens, 104–139 mm SL, 19 January 2013; Re River, Sơn Hà, Quảng Ngãi Province, Vietnam (15°01'03.9"N, 108°31'55.0"E): UF 249109, 5 specimens, 99–150 mm SL, 24 February 2018.

Figure 5. 

Poropuntius anlaoensis A adult holotype (UNS00762, 139.46 mm SL) in life B in preservative C ventral view of head D dorsal view. Scale bars: 10 mm.

Diagnosis

Poropuntius anlaoensis is the only species of the genus found on the coastal side of the Annamite Cordillera and nowhere else. It differs from all other species of Poropuntius genetically (Fig. 2A), and by having distal margin of dorsal fin distinctly concave (vs straight to slightly concave). It most closely resembles P. deauratus but has 29–31 (vs 25–28) lateral-line scales, snout distinctly pointed (vs slightly pointed), and caudal fin light yellow with bold black submarginal stripes (vs bright lemon yellow to dusky with bold to faint black submarginal stripes). Poropuntius anlaoensis differs from P. genyognathus, P. hampaloides, and P. melanogrammus in having barbels (vs no barbels); from P. heterolepidotus and P. hathe in having scales on posterior half of body not markedly smaller (vs markedly smaller) than those on anterior half; from P. alloiopleurus, P. burtoni, P. carinatus, P. huangchuchieni, P. kontumensis, P. krempfi, P. laoensis, P. opisthoptera, and P. schanicus in having 29–31 (vs > 32) lateral-line scales and bold black submarginal stripes (vs no bold black stripes) on caudal fin.

Description

General appearance in Fig. 5; meristic and morphometric data of 11 specimens in Table 3. Head conical, longer than deep, depth 1.2–1.4 × in HL. Snout pointed. Tubercles tiny and few on tip of the snout, many irregular transverse rows of small tubercles reaching front of eyes in male. Mouth subterminal and oblique, extending posteriorly in length slightly longer than eye diameter and broadly horseshoe-shaped (Fig. 5C). Rostral barbel shorter than maxillary barbel, both longer than eye diameter.

Table 3.

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Morphometric and meristic characters of Poropuntius anlaoensis sp. nov., n = 11 including holotype.

	Poropuntius anlaoensis
	Holotype UNS00762	Range	Mean ± SD / mode
SL (mm)	139.46	99.2–150.9	118.6 ± 16.4
Morphometrics
% SL
Total length	127.6	124.8–129.3	127.1 ± 1.4
Fork length	108.1	107.2–109.7	108.3 ± 0.6
Body depth	31.4	29.9–35.7	31.6 ± 1.5
Body width	13.5	13.5–16.3	14.8 ± 0.7
Head length	24.4	22.4–25.7	24.4 ± 1.2
Caudal peduncle length	22.5	18–23.9	21.1 ± 1.6
Caudal peduncle depth	10.9	10.9–13.4	11.9 ± 0.7
Dorsal-fin base length	15.6	15.6–18.8	16.2 ± 0.9
Dorsal-fin length	25.8	21.4–29.7	25.3 ± 2.1
Anal-fin base length	8.9	8.4–10.5	9.3 ± 0.6
Anal-fin length	16.2	14.8–21.3	16.5 ± 1.8
Pectoral-fin length	22.1	20.2–22.6	21.4 ± 0.8
Pelvic-fin length	18.7	16.8–20.9	18.8 ± 1.1
Predorsal length	48.8	44.5–49.4	48.1 ± 1.2
Prepectoral length	21.3	19.8–23.7	21.6 ± 1
Preanal length	72.2	69.7–75.2	72.5 ± 1.6
Prepelvic length	48.0	46.5–50.8	48.6 ± 1.4
Pelvic-fin base to anal-fin base	22.0	18.8–22.8	21.1 ± 1.1
Pectoral-fin base to pelvic-fin base	25.5	21.3–26.2	23.4 ± 1.6
% HL
Head depth at nape	84.3	44.5–84.3	76.6 ± 10.7
Head width	56.7	54.8–63.7	58.3 ± 2.5
Snout length	30.8	26.3–35.8	29.5 ± 2.6
Interorbital width	35	32.9–41.9	37.9 ± 2.7
Eye diameter	23.5	23.5–27.3	25.9 ± 1.1
Mouth width	30.8	25.4–33.2	29.6 ± 2.5
Rostral barbel length	38.2	23.1–38.2	30.4 ± 4
Maxillary barbel length	31.4	23.3–39	33.4 ± 4.3
Counts
Dorsal-fin spines and rays	iv,8.5	iv,8.5
Anal-fin spines and rays	iii,5.5	iii,5.5
Pectoral-fin spines and rays	i,15	i,11–16	mode = i,15
Pelvic-fin spines and rays	i,8	i,8
Lateral-line scales	29	29–31	mode = 30
Transverse scales rows above lateral-line	5.5	5.5
Transverse scales rows below lateral-line	3.5	3.5
Circumferential scale rows	20	20–22	mode = 22
Circumpeduncular scale rows	14	14
Predorsal scales	11	10–12	mode = 10
Scales from end of anal-fin base to caudal-fin origin	8	7–9	mode = 7
Serrae on last simple dorsal-fin ray	24	16–27	mode = 24

Body moderately deep and compressed, depth approximately 2.8–3.3 × in SL. Dorsal body profile convex, slightly convexity from nape with narrow dorsum almost straight in front of dorsal origin to dorsal fin. Base dorsal fin decreasing in height nearly straight dorsal margin of the body, extending from dorsal-fin origin to narrowest part of the caudal peduncle. Ventral profile rounded, rising through anal-fin insertion to caudal-fin base. Caudal peduncle slender, moderately shallow and long, 1.6–2.1 × longer than deep. Anus immediately in front of anal fin. Lateral line complete, 29–31 scales; 10–12 predorsal scales; 5/1/3 scales in transverse row anterior to pelvic-fin origin. Lateral-line tubes extending at least halfway across each scale, with accessory pore on ventral branch on nearly every lateral-line scale. Dorsal iv-8.5, pectoral i-15, pelvic i-8, and anal iii-5.5.

Dorsal fin high and sharply pointed at apex, last unbranched ray longest, followed by first branched ray which is considerably shorter. Last unbranched ray ossified with 18–20 serrae. Posterior extensions of serrae forms straight line, with base line curved posteriorly. More distal denticles curved along their lengths. Distal margin of fin strongly concave, with posteriormost ray equalling length of third branched ray. Dorsal-fin origin approximately opposite pelvic-fin origin. Dorsal-fin base longer than anal-fin base.

Pectoral fin long, extending to third scale row before pelvic-fin origin.

Pelvic fin not extending to base of last unbranched anal ray. Distal margin concave near tip with falcate apex. Axillary scale present at base of pelvic fin.

Anal fin moderate, distal margin straight when fin is erect.

Caudal fin deeply forked with outer rays nearly 4 × length of middle rays. Upper and lower lobes nearly equal in length with straight distal margin on each lobe.

Colour in life

Head dark greenish golden on top, greenish golden around orbit and on opercula, white on lower jaw. Body primarily silvery but greenish golden on dorsally to lateral line, scale bases with melanophores. All fins except caudal hyaline with pinkish orange tinge on branched rays; fins more darkly pigmented in adults. Caudal fin yellow with bold black submarginal stripes (Fig. 5A).

Colour in preservative

Body including head dark brown on back. Opercula dark at base. Lower half of body light brown. Scale margins lined with brown, forming network. All fins brown to dark brown (Fig. 5B).

Etymology

Specific epithet is in reference to the type locality, the An Lão drainage.

Suggested common name

Cá hồng nhau An Lão (Vietnamese), Anlao brook barb (English).

Distribution

Poropuntius anlaoensis is restricted to the southern Annam ecoregion and is possibly endemic to the coastal side of the Annamite Cordillera.

The objective of this study was to test, using molecular data, the species diversity of Poropuntius, especially that of Vietnam in which 15 species names have been recognised recently as valid. As noted above, most species of Poropuntius have been described using only morphological data, and recent investigations using molecular data suggested that some morphological hypotheses were incorrect. Our data indicate that 17 names assigned to species are synonyms.

Several factors led to the inflation of species names for Poropuntius. These include limited efforts overall in collecting and classifying cyprinid fishes, especially in northern Vietnam, limited access to type specimens in European museums, limited availability of publications (often in foreign languages – although now this is being alleviated by online access), inadequate descriptions containing limited information, and failure to appreciate morphological variation related to trophic diversification within species. Finally, a substantial portion of the cyprinid diversity of northern Vietnam is shared with that of southern China, but researchers in the two countries have not had access to specimens from both countries or to original descriptions in other languages. Consequently, studies were limited to in-country fauna, and species in each country were treated as endemic to that country.

Ecomorphological variation in Poropuntius was described and figured by Roberts (1998: figs 6, 8), and Kang et al. (2016) interpreted P. bolovenensis, P. lobocheiloides, and P. solitus as ecomorphs of P. bolovenensis. The often-extreme intraspecific phenotypic variation in the shape of the mouth and lips, and in the development of the horny sheath on the lower jaw, has led to taxonomic confusion in Poropuntius. Ecophenotypic variation is expressed especially clearly in species occupying pools isolated by barriers such as waterfalls in streams on plateaus at high elevations (e.g., on the Bolaven, Kontum, and Langbiang Plateaus) and in drainages leading to the Gulf of Tonkin (in the Song Hong and Annam ecoregions). Species not exhibiting such extreme polymorphism may nevertheless carry information in their genomes necessary to generate an array of potentially taxonomically confusing, continuous variation as well as more disjunct phenotypes. For example, the position of the dorsal fin, often used in taxonomic diagnoses, varies from more anteriorly to more posteriorly positioned in Poropuntius, as seen in P. alloiopleurus, P. huangchuchieni, and P. laoensis (Wu et al. 2013; this study). Specimens of Poropuntius from flowing water habitats are characterised by a more elongated body and a relatively long caudal peduncle, while those from pools have a deeper body and larger unpaired fins (Figs 3A, B, D, E, 4G, H). Similar patterns have been described in other cyprinids, e.g., Rasbora paviana and Lobocheilos rhabdoura, with populations inhabiting fast-flowing streams having more slender bodies than those inhabiting slower-flowing habitats (Stolbunov et al. 2011; Ciccotto and Page 2016).

During a decade of field work on Southeast Asian freshwater fishes, the first author and colleagues have collected samples of P. deauratus, P. krempfi, P. alloiopleurus, and P. laoensis revealing marked intraspecific phenotypic variation. These samples include those from river basins in which few or no fish collections have been made or reported upon previously, and which fill in gaps in the distributions of these species. Pronounced variation among adult individuals in these species has been observed in body depth, dorsal-fin spine length, ossification and serration of the last simple dorsal-fin ray, body colour, and caudal fin colour. For example, in the wide-ranging P. deauratus, the typical colour in life is a silvery to light green gold body with bright yellow on the posterior half of the body and a bright lemon-yellow caudal fin with bold black submarginal stripes. However, colour in this species may be much more subtle with the body uniformly dusky to dark and the fins dusky (Fig. 4B, H).

This study has revealed that scientific names have been applied erroneously to populations of P. krempfi, P. alloiopleurus, P. huangchuchieni, P. laoensis, P. kontumensis, and P. deauratus. Errors in the taxonomy of Poropuntius have resulted primarily from inadequate sampling and reliance on characters that vary intraspecifically. Additional samples from unsampled or poorly sampled populations allowed the use of molecular data to test previous species hypotheses. More sampling and use of molecular as well as morphological data on species of Poropuntius that could not be included in this study are likely to require additional taxonomic changes.

Võ Thị Bích Thảo assisted with lab work. Anonymous peer reviewers scrutinised and commented on the manuscript. For all of this assistance we are most grateful.