Prognathorhynchus eurytuba Ax & Armonies 1987

• Main Authors: Reygel, Patrick C., Willems, Wim R., Artois, Tom J.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2011
• Subjects: Biodiversity; Taxonomy; Animalia; Platyhelminthes; Rhabditophora; Rhabdocoela; Gnathorhynchidae; Prognathorhynchus; Prognathorhynchus eurytuba; North West Atlantic
• Online Access: https://doi.org/10.5281/zenodo.6189695; http://treatment.plazi.org/id/F24C880C1F459D2E6093A43EFD07FE27

Prognathorhynchus eurytuba Ax & Armonies, 1987 (Fig. 1) New locality. Santa Cruz Island, Bahia Academy, stations IX5 e and IX 5 f. Known distribution. North West Atlantic: several localities in New Brunswick, Canada and in South Carolina, USA (see Ax & Armonies 1987; Ax 1997). Material. Four individuals studied alive, five sagittally-sectioned specimens (ZMUG 23317-23321). Remarks. The Galapagos specimens can easily be identified as P. e u r y t u b a , based on the overall organisation of the body, the morphology of the proboscis hooks and that of the stylet. As the original description by Ax and Armonies (1987) and a later account by Ax (1997) were based only on observations on live animals, very little is known of the detailed morphology, and a reconstruction of the genital system is lacking. The new material from the Galapagos allows a detailed and more complete description, although certain features are still hard to discern, especially concerning details of the female system, which appears to be difficult to study in members of the taxon Prognathorhynchus Meixner, 1929 (see Karling 1947; Brunet 1973; Ax & Armonies 1987). Live animals about 0.7−0.8 mm long. The cellular epidermis (± 5 µm thick) is ciliated over the entire body (cilia ± 5 µm long). A few sensory bristles (± 20 µm long) are present around the proboscis opening. The proboscis hooks (Fig. 1 C) are as described by Ax and Armonies (1987), only slightly larger. The diameter of the basal plate is ± 25 µm (Ax & Armonies 1987: 17 µm). The stylet’s (Fig. 1 B) shape is as illustrated by Ax and Armonies (1987). The stylet length in the Galapagos specimens varies from 42−48 µm ( x = 45 µm; n = 3), which is longer than in the Canadian (Ax & Armonies 1987: 32 µm) and the specimens from South Carolina (Ax 1997: 35 µm). The common genital pore (Fig. 1 A, D: gp) is situated ventrally, very close to the caudal end and opens into a tubiform common genital atrium, which is lined with a low, anucleated epithelium and is surrounded by a ...