Proteocephalus sagittus La Rue 1911

3.2.1. Proteocephalus sagittus (Grimm, 1872) La Rue, 1911

Fig. 2

Syns.: Ichthyotaenia sagitta Grimm, 1872; Proteocephalus pamirensis Dzhalilov and Ashurova, 1971

Type host: Barbatula barbatula (Linnaeus, 1758) (Cypriniformes: Nemacheilidae).

Other hosts: Cobitis ‘ taenia ’ Linnaeus, 1758 (Cypriniformes: Cobitidae) (several species of loaches have been reported under this name — [2]); Triplophysa stoliczkai (Steindachner, 1866) (Cypriniformes: Nemacheilidae).

Site of infection: intestine.

Type locality: Saint Petersburg, Russia.

Type material: not known to exist.

Distribution: Europe (British Isles, Czech Republic, Hungary, Latvia, Russia, Slovak Republic, Ukraine), Palaearctic Asia (Russia — basins of the rivers Volga, Ob and Irtysh, Tajikistan).

Selected references: Grimm (1872) [26], Freze (1965) [5], Dzhalilov and Ashurova (1971) [27], Scholz and Hanzelová (1998) [12], Scholz et al. (2003, 2007) [11,13], Jarkovský et al. (2004) [28], and Hypša et al. (2005) [10].

This species was described as Ichthyotaenia sagitta by Grimm (1872) [26] and transferred to Proteocephalus by La Rue (1911) [29]. Scholz and Hanzelová (1998) [12] synonymized this species with P. torulosus, a specific parasite of cyprinid fishes in the Holarctic Region [12]. However, a subsequent study of new material as well as a comparative analysis of partial ssrDNA and 5.8S-ITS2 rRNA gene sequences delineated these as separate species [11,13]. The present study provides strong support for the validity of P. sagittus and made it possible to supplement species diagnosis by additional measurements not reported in the previous morphological descriptions (see [12,13,30]; Table 2).

Proteocephalus sagittus has been found in Europe and parts of Palaearctic Asia [5,12]. Barbatula barbatula, which is the type host of this cestode, is found in most parts of Europe [1], but records of P. sagittus from this fish host are relatively scarce [3]. Proteocephalus sagittus has also been found in the cobitid Cobitis ‘ taenia ’ in Europe and nemacheilid Triplophysa stoliczkai in Tajikistan,but no material suitable for molecular evaluation was available to test whether tapeworms from these hosts are actually conspecific with P. sagittus.

Records of P. sagittus from fishes other than loaches, such as Cottus gobio (Perciformes: Cottidae), Gobio gobio, Leuciscus leuciscus (Cypriniformes: Cyprinidae), and Salvelinus alpinus (Salmoniformes: Salmonidae) (e.g. [31,32]; see [3] for exhaustive list of records), are considered erroneous.