Systematic revision of the genera of Pangasiidae (Rudhy Gustiano) SYSTEMATIC REVISION OF THE GENERA OF PANGASIIDAE (SILURIFORMES, OSTARIOPHYSI) Rudhy Gustiano*) and Laurent Pouyaud**) ABSTRACT The family Pangasiidae belongs to the suborder Siluroidei, order Siluriformes, and suborder Ostariophysi. Since the groups were established as Pangasiini Bleeker, 1858; its content and classification have been greatly changed. Judging from the literature, the main constraint to cultivate wild species and to optimize the production of cultured species is needed to the poorly documented systematics of this family. Therefore the objective of the present study is to provide the diagnostic characters and the keys for identification the genera of Pangasiidae. The results clearly demonstrate that biometrically four natural groups can be distinguished. They are the genus Helicophagus, Pangasianodon, Pteropangasius, and Pangasius. The diagnosis of the family, the identification key of the genera and the description are given. KEYWORDS: taxonomy, biometrics, catfish, Pangasiidae, Helicophagus, Pangasianodon, Pteropangasius, Pangasius INTRODUCTION Valenciennes, 1840 with 19 valid species. Recently, seven new species were added to Related to taxonomy, the typology species the genus Pangasius (Pouyaud et al., 1999; concept using biometric characterization, al- Roberts, 1999; Pouyaud & Teugels, 2000; though sometimes considered “classical”, is Pouyaud et al., 2002; Gustiano et al., 2003) still a powerful method to determine different and another one was described in the genus taxa. In many cases, biometrics is very useful Helicophagus (Ng & Kottelat, 2000). Following to segregate different taxa in the field. During Vidthayanon & Roongthongbaisuree (1993), the past 20 years, various biometric analyses Pangasius consists of four subgenera: (1) have been applied on many catfish families Pangasius (Pangasianodon) Chevey, 1930 and fish in general to provide correct diag- diagnosed by the absence of mandibular noses of taxa and keys (Teugels, 1986; De Vos, barbels, the absence of teeth in adults and 1995; Retzer & Page, 1997; Reis, 1997; the presence of a single swimbladder, and Armbruster, 1998; Ng & Ng, 1998). including P. hypophthalmus Sauvage, 1878 Smith (1945) recognised four genera in the and P. gigas Chevey, 1930; (2) Pangasius Pangasiidae; they are Helicophagus Bleeker, (Pteropangasius) Fowler, 1937 with four lobes 1858; Pangasius Valenciennes, 1840; in the swimbladder and with multiple segments Pteropangasius Fowler, 1937; Pangasianodon in the last lobe and consisting of P. Chevey, 1930. Roberts & Vidthayanon (1991) pleurotaenia Sauvage, 1878 and P. in a systematic revision of Pangasiidae, micronemus Bleeker, 1847; (3) Pangasius recognised two genera: Helicophagus Bleeker, (Neopangasius) Popta, 1904 with palatal teeth 1858 with two valid species and Pangasius arranged in a single large patch, high vertebral *) Research Institute for Freshwater Aquaculture, Bogor, Indonesia **) Institut de Recherches pour le Dévelopment (IRD), Indonesia - France 13 Indonesian Aquaculture Journal Vol.3 No.1, 2008 counts and containing P. nieuwenhuisii Popta, tip of fin; anal fin height (AFH) from base of first 1904, P. humeralis Roberts, 1989, P. lithostoma anal fin ray to tip of longest ray; anal fin length Roberts, 1989, P. kinabatanganensis Roberts (AFL) from base of first ray to base of last anal & Vidthayanon, 1991; and (4) Pangasius ray; adipose fin height (ADFH) from base to tip; (Pangasius) Valenciennes, 1840 for which no maximal adipose fin width (ADFW); maximal or- diagnostic features are provided and which bital diameter (ED); mouth width (WM); lower jaw includes all remaining species. Molecular phy- length (LJL) from tip of snout to corner of mouth; logenies published by Pouyaud et al. (2000) interorbital distance (WT) taken between the confirm the subgeneric classification proposed eyes; distance snout to isthmus (DSI) from tip for Pangasius except for Pangasius of snout to isthmus with a closed mouth; pos- (Neopangasius) which is polyphyletic and tocular length (OL) from posterior border of eye which should be included in Pangasius to posterior border of operculum; maxillary (Pangasius). Gustiano (2003) raised the barbel length (MBL); mandibular barbel length subgenera proposed by Pouyaud et al. (2000) (MABL); body width (BW) from left to right scapu- based on osteological analysis. lar excrescence bones close to pectoral spine base; prepectoral length (PPEL) from tip of snout In this study, it presents the results of a to pectoral spine base; prepelvic length (PPL) biometrical analysis of Pangasiidae genera in from tip of snout to first pelvic fin ray base; order to provide the diagnostic characters and vomerine width (VMW); vomerine length (VML); the key for identification of the genera. palatine length (PAL); palatine width (PAW); dor- sal spine width (DSW) taken at base of second MATERIALS AND METHODS dorsal spine. The following meristic counts Nine hundred and ninety nine specimens, were noted: number of gill rakers on the first collected during the “Catfish Asia” project branchial arch, number of dorsal, pelvic, pec- (Legendre, 1999), formed the core of the mate- toral and anal fin rays. An illustration of the rial examined during this study. The material measured characters is shown in Gustiano from all other examined specimens was (2003) and Gustiano & Pouyaud (2007). sampled in Bangladesh, India, Vietnam, Cam- bodia, Laos, Thailand, Malaysia, and Indonesia. Genera Characterization Additional material including the types of pre- Data were subjected to principal compo- viously described genera housed in various nent analysis (PCA) (Bookstein et al., 1985) us- museums was also examined. ing the CSS Statistica package (Stat Soft, Inc.), On each specimen, 35 point to point mea- version 4.5 in order to define structuring char- surements covering the possible variation of acters. For this purpose, measurements were the body conformation were taken using dial log-transformed in order to minimise the effect callipers as follows: standard length (SL) from of non-normality before the PCA was run on tip of snout to caudal peduncle; head length the covariance matrix. The first factor, consid- (HL) from tip of snout to posterior border of ered as the size-factor was not taken into ac- operculum; snout length (SNL) from tip of snout count, in order to minimise the effect of size to anterior eye border; anterior snout width differences between the samples. Allometry (SNW1) taken between the anterior nostrils; the is indicate by unequal loadings of variable on posterior snout width (SNW2) taken between the first component, and biological interpreta- tion of allometric data proceed using coeffi- posterior nostrils; head depth (HD) taken at the cients of the first components against the sec- level of the posterior eye border; head width ond components that was linear. Missing data (HW) inter-orbital length taken on frontal part of were casewise deleted. An independent PCA the head; predorsal distance (PDL) from tip of was run on the correlation matrix from the snout to base of first dorsal spine; caudal pe- untransformed count data. Finally, data analy- duncle length (CPL) from base of last anal fin sis consisted in characterising groups from ray to middle of caudal peduncle; caudal pe- scatter plots between pairs of structuring char- duncle depth (CPD) taken as minimum body acters for subsequent use in generic identifi- depth; pectoral spine length (PESL) from its base cation keys. to its tip; pectoral fin length (PEFL) from pecto- ral spine base to tip of fin; dorsal spine length RESULTS AND DISCUSSIONS (DSP) from base of first dorsal spine to tip; dor- sal fin length (DFL) from base of first dorsal spine Based on the analysis of 35 measured and to tip of fin; pelvic fin length (PFL) from base to five counted characters, the diagnosis of the 14 Systematic revision of the genera of Pangasiidae (Rudhy Gustiano) family, the identification key of the genera, and snout, the adipose fin height, the width of the description are given below. mouth, and the anal fin length. The components of PCV are dominated by the eye diameter, the Pangasiidae adipose fin width, the postopercular length, the distance snout to isthmus, the predorsal Morphologically, pangasiid catfishes are length and the dorsal spine width. The first recognized by a laterally compressed body, group includes the type species of the genus the presence of two pairs of barbels (one pair Helicophagus Bleeker, 1858 (type Helico- of maxillary and one pair of mandibular), the phagus typus Bleeker, 1858b). The second relatively long anal fin, and short dorsal fin with group contains the other species. Further two spines (first small and hidden under the analysis using the dominant characters skin), adipose fin small with free posterior mar- showed that the first group differs from the gin. remaining group by the combination of a slen- The first step of the analysis is to define der anterior snout (<16.5% HL) and a predorsal how many natural groups can be recognised length of 34.5%—40.5% SL (Figure 2). in the Pangasiidae. A PCA using the covariance matrix for 27 measurements on the 657 speci- When plotting the PCII and PCIV (Figure 3) mens results in two groups (Figure 1). The first derived from a PCA on 27 variables taken on group is entirely isolated on the negative sec- 657 specimens, we can distinguish one group tor of PCIV and the sector of PCV, while the entirely situated on the negative sector of PC second group is mostly located on the right of II and only slightly overlapping on PC II with the first group and it has a lower score on the the other specimens. This group includes the PCV. The factor loadings (Table 1) show that type species of the Pangasius (Pteropangasius) the components of PCIV are dominated by the Fowler, 1937 (type Pteropangasius cultratus, size of the vomerine toothplate (length and Smith, 1931) and Pseudolais Vaillant, 1902 (type width), the mandibular and maxillary barbel Pseudolais tetranema Vaillant, 1902). Pseudolais length, the anterior and posterior width of was considered a junior synonym of Pangasius 4 3 2 1 0 PCV -1 -2 -3 -4 -4 -3 -2 -1 0 1 2 3 PCIV Figure 1.