Pentaloculum macrocephalum Alexander, 1963

Bueno, Veronica M. & Caira, Janine N., 2023, Phylogenetic relationships, host associations, and three new species of a poorly known group of “ tetraphyllidean ” tapeworms from elasmobranchs, Zootaxa 5254 (1), pp. 30-50 : 33-35

Pentaloculum macrocephalum Alexander, 1963 emended

( Fig. 2A–F )

Type and only known host: Typhlonarke aysoni (Hamilton) , blind sleeper ray; ( Torpediniformes : Narkidae Fowler ).

Type locality: New Zealand .

Site of infection: Spiral intestine.

Specimens deposited: SEM voucher LRP No. 10949 (CR-136-A); scolex prepared for SEM retained with JNC at the University of Connecticut.

Sequence data: KF685877 and OQ186458 (hologenophores, LRP Nos. 8347 [CR-136, TE-171] and LRP No. 9826 [CR-136-1, VB229]).

Emendation. Based on one scolex observed with SEM and its strobilar voucher.

The description of this species by Alexander (1963) should be emended to include the following information on the configuration of the microtriches of the scolex and proglottid anatomy.

Apex of scolex not observed ( Fig. 2A ); distal bothridial surfaces ( Fig. 2B ) and all proximal bothridial surfaces ( Figs. 2D – F ) densely covered with long-tipped aristate gladiate spinitriches, gladiate spinitriches, and capilliform filitriches. Cephalic peduncle ( Fig. 2C ) densely covered with large gladiate spinitriches, filitriches not observed.

Vitelline follicles arranged in two lateral bands; lateral bands confluent posterior to ovary.

Remarks. The specimen of P. macrocephalum examined here with SEM and light microscopy was collected from the same individual of Typhlonarke aysoni as the specimen provisionally identified as Pentaloculum n. sp. 1 in the molecular phylogenetic analysis of Caira et al. (2014), in which the host was identified as T. tarakea . We have followed Eudy et al. (2019) in referring to this cestode taxon as P. macrocephalum and this host taxon as T. aysoni . Comparison of the hologenophore of the specimen included in the analysis of Caira et al. (2014), which was fixed in ethanol, with the whole mount of the strobila of the specimen examined here with SEM, which was fixed in formalin, confirms this identification.

Figures

FIGURE 2. Scanning electron micrographs of Pentaloculum macrocephalum Alexander 1963. (A) Scolex, small letters indicate location of details in micrographs B–F. (B) Distal bothridial surface densely covered with long-tipped aristate gladiate spinitriches interspersed with gladiate spinitriches and capilliform filitriches. (C) Cephalic peduncle densely covered with large gladiate spinitriches, filitriches not observed. (D) Proximal surface of anteriormost loculus densely covered with longtipped aristate gladiate spinitriches interspersed with gladiate spinitriches and capilliform filitriches. (E) Proximal surfaces of anterior pair of loculi densely covered with long-tipped aristate gladiate spinitriches interspersed with gladiate spinitriches and capilliform filitriches. (F) Proximal surfaces of posterior pair of loculi densely covered with long-tipped aristate gladiate spinitriches interspersed with gladiate spinitriches and capilliform filitriches.