Barbus rajanorum
Year: 2025
Type: other
Abstract: Barbus rajanorum. Heckel (1843) described B. rajanorum from the Qweiq at Aleppo. He counted 65 total lateral-line scales in this species, the same as those represented on the figure by Heckel (1843: Fig. 1 on Plate 14, reproduced here as Fig. 5), and in the type of the species NMW 54494 (Fig. 6) examined by JF. Karaman (1971) listed L. rajanorum as a valid species without examining the type, but Almaça (1991:64) identified B. rajanorum as a hybrid. Also, Coad (1991) identified it as a hybrid between Luciobarbus pectoralis and Capoeta damascina, providing F. Krupp (in litt. 1986) as a reference for this statement. Nevertheless, Fareed Krupp (pers. comm. 2022) has since clarified that this statement was likely made in a personal communication, and not in any published work, suggesting that Coad (1991) may have confused this with Almaça (1991) and Coad (1995), reproducing the classification of the species from his 1991 publication. Later authors, including Freyhof et al. (2021), followed Coad (1991) without critical evaluation. As L. pectoralis is endemic to the Eastern Mediterranean basin and likely never occurred in the Qweiq (see discussion below in the chapter about L. kersin), it certainly cannot be one of the parental species. Therefore, Barbus rajanorum is identified as the hybrid between L. schejch and C. damascina. Hybrids between Luciobarbus and Capoeta (Fig. 7) are frequently found in nature, but cannot be easily identified. The head and mouth shapes, as well as the length of the barbels, are the key characters that distinguish Luciobarbus from Capoeta. These are quite variable in Capoeta, and hybrids bridge the gap between both genera. Hybrids are identified by their unequal number of chromosomes, as all Luciobarbus are tetraploid and Capoeta are hexaploid (Yang et al. 2015). This character cannot be examined in the field or on preserved materials. Compared to Capoeta, Luciobarbus x Capoeta hybrids possess relatively longer heads, and two pairs of long barbels (vs. one pair of short barbels in C. damascina), and the lower jaw is much less or not keratinised. There is also a thin but usually fully developed lower lip in the hybrids (vs. interrupted in Capoeta). Compared to Luciobarbus, the most evident characters in the hybrids are the stouter and deeper body; thinner last unbranched dorsal-fin ray, blunt head, and shorter snout. Also, the lower lip is often interrupted and thin, never fleshy, or with a median lobe, as in many Luciobarbus. Following Coad (2021), L. barbulus (= L. schejch) has 46–59 total lateral line scales, and following Alwan (2010), C. damascina has 75–90 total lateral line scales, based on fishes analysed from the Euphrates and Tigris. The type specimen of B. rajanorum, having a short snout, thin lips and no keratinised lower jaw, has 65 scales, fitting perfectly between L. schejch and C. damascina. Berg (1949) included L. mystaceus and L. schejch as synonyms of B. rajanorum, and Ladiges (1960), and Karaman (1971) followed this opinion. However, there is no reason to reject the hypothesis by Almaça (1991) (that L. rajanorum is a hybrid), as we also identify L. rajanorum as a hybrid. Heckel (1843) had already pointed out the high similarity of B. rajanorum to C. damascina, but he described it as a species of Barbus.As a hybrid, B. rajanorum is an unavailable name for the Luciobarbus species of the Euphrates and Tigris, as there are no indications that these hybrids might have formed their own reproductive unit independent from their parental species. Luciobarbus mystaceus. From the description by Pallas (1814:293), it is evident that L. mystaceus is a synonym of L. mursa, a species endemic to the Caspian Sea basin, and its type locality is in the Kura River. Already, Heckel (1843:252) indicated that Pallas’s L. mystaceus is identical to L. mursa. Heckel (1843) is not the author of L. mystaceus, as he only identified some of his material as this species. Potentially, it was Karaman (1971), followed by Almaça (1986), who suspected that Heckel (1843) was the first author of L. mystaceus, and that the species has its type locality in the Tigris in Mosul. Subsequent authors followed this opinion, leading to widespread confusion (see Tsigenopoulos et al. 2003, Kaya et al. 2016, Valiallahi & Coad 2017a). Berg (1949) pointed out that L. mystaceus is based partly on L. mursa and L. capito, while Bogutskaya et al. (2003) considered it as most probably a synonym of L. capito. Neither L. capito nor L. mursa have been confirmed from Mosul or other places in the Persian Gulf basin. The fish identified as L. mystaceus (Fig. 8–10) by Heckel (1843) are housed at NMW and are not conspecific with L. mursa, but with L. schejch. Barbus barbulus. Luciobarbus barbulus was described by Heckel (1849) based on syntypes from the Mond in the Iranian Gulf basin, and from the Qweiq in Syria. Only the syntype (NMW 6596, Fig. 11) from Iran is available at NMW. The molecular analysis in Khaefi et al. (2017), and the morphological analysis in Valiallahi & Coad (2017a, b), and results of the current study, suggest that L. barbulus is not endemic to the Mond but also occurs widely in other rivers of the Persian Gulf, including the Tigris. As we find no characters to distinguish NMW 6596 from L. schejch, L. barbulus is treated as a junior synonym of L. schejch. This issue was not resolved earlier, as types of L. schejch have thin, not fleshy lips, and so it was identified as L. pectoralis, while fish with thick lips were identified as L. barbulus (see discussion below). Luciobarbus schejch. Heckel (1843) distinguished his materials identified as L. mystaceus from sympatric L. schejch (Fig. 8) by the width of the fleshy lips with a central lobe in L. mystaceus (vs. thin, without a lobe in L. schejch). However, what Heckel considered a “central lobe” is a mental pad following the nomenclature of Kottelat & Freyhof (2007), which can become pendulous as the fish grows. This character has also been widely used to distinguish fish identified as L. pectoralis (with thin lips) from those identified as L. barbulus (with thick, fleshy lips) in the Persian Gulf basin (Coad 2010). The length and strength of the last unbranched dorsal-fin ray are often mentioned as additional characters that distinguish these species. Günther (1868) had already mentioned that the presence or absence of a median lobe/pad in the lower lip is of no taxonomic value as its development is subject to great variation. Also, Krupp (1985), who studied fish identified as L. pectoralis and L. barbulus, mentioned that the size of the mental pad in the lower lip, thickness of the lips, as well as the strength and length of the last unbranched dorsal-fin ray, are highly variable characters not suitable to distinguish these species. Recently, Khaefi et al. (2017:838) analysed fish identified as L. barbulus by molecular characters and again found the median pad/lobe quite variable: i.e., “with or without a median lower lip lobe”. The thickness of the lips, and the presence or absence of the median pad have been demonstrated to be very variable in other Luciobarbus species, especially in North Africa (Brahimi et al. 2017, 2018), and questioned as a taxonomic character in African Labeobarbus by Vreven et al. (2016), where different shapes of lips are widespread within populations. There is no published evidence to consider the fish identified as L. mystaceus by Heckel (1843) as a species distinct from L. schejch. Indeed, some syntypes of L. schejch (Figs. 12–13) have a surprisingly short snout compared to Heckel’s L. mystaceus (Fig. 8–10) and we understand, that earlier authors hesitated, to identify them as the same species. Heckel’s L. schejch and L. mystaceus could easily be differentiated by this character if only these individuals were available. But L. schejch is very variable in its body shape and snout length (see below, Fig. 12–16, 20–21, 31–36), and the individuals identified as L. mystaceus by Heckel (1843) are here recognised as L. schejch as we find no difference to distinguish them from others. Heckel (1843) already noted that the local fishers in Mosul (“die Araber [the arabs]”) did not distinguish between L. schejch and L. mystaceus. Fish identified as L. schejch and L. mystaceus by Heckel (1843) correspond to those identified by Coad (2010) as L. barbulus, L. pectoralis and L. xanthopterus in the Gulf basin. As L. xanthopterus is an unavailable name (see below), L. pectoralis is endemic to the Mediterranean basin, and L. schejch has priority over L. barbulus, L. schejch is the name available for this widespread species. Luciobarbus schejch is diagnosed by having 11–24 total gill rakers on the first arch, 50–62 total lateral-line scales, snout length 1.1–1.9 times postorbital length, and an inferior or slightly subterminal mouth. Many individuals (but not all), especially juveniles, have a long and strong last unbranched dorsal-fin ray (Fig. 13–14, 32–34), a character state not seen in other Luciobarbus in the Persian Gulf basin, and certainly not in L. pectoralis from the adjacent Mediterranean basin. Coad (2010) also reported relatively low numbers of total lateral-line scales in L. schejch (43), but on our materials, the lowest number counted was 52, from an individual collected in Iran. The variability of head and body shapes, as well as the colouration of live individuals in L. schejch, is indeed surprising (Fig. 12–16, 20–21, 31–36) and is likely the reason why it was not previously understood whether these fish are indeed conspecific. We fully appreciate authors such as Heckel (1843) and Valiallahi & Coad (2017a), who were confident of identifying more than one species in what we call L. schejch in our study. If just character extremes are compared, such as silvery stout or blackish fishes with thin lips, and slender, yellowish individuals with thick lips, we would also have suggested that two species are involved. Especially in wetlands and l
Language: English
Subfield: Aquatic Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W6911903426
Cites:
Cited by:
Related to: