Carcharodorhynchus papillaris, Diez & Reygel & Artois, 2019

Diez, Yander L., Reygel, Patrick & Artois, Tom, 2019, Schizorhynchia (Platyhelminthes, Rhabdocoela) from eastern Cuba, with the description of fifteen new species, Zootaxa 4646 (1), pp. 1-30 : 15

Carcharodorhynchus papillaris sp. n.

( Fig. 9 )

http://zoobank.org/ urn:lsid:zoobank.org:act:01734072-BF6B-4DAD-98DD-C4BD54A2B471

Material. One specimen studied alive and whole mounted, designated holotype ( FMNH https://id.luomus.fi/ KV.614), collected in Bueycabón (type locality) (May 25, 2018), sublittoral, fine-grained sand with organic matter, 0.5 m depth, salinity 35 ‰.

Etymology. The epithet refers to the fact that the copulatory bulb ends in an unarmed papilla.

Diagnosis. Species of Carcharodorhynchus with symmetric proboscis, lips 145 µm long. The belts of denticles show a ‘basal gap’; denticles shark-tooth shaped, 0.9 µm long in the basal half of the belts and 3 µm long in the distal half. A single seminal vesicle opens into the copulatory bulb. Copulatory bulb 102 µm long and 29 µm at the widest point, without hard structures, distally ending in a muscular penis papilla.

Description. Live animal about 2 mm long, yellowish, without eyes. Proximal end of the body uncoloured. There is a pale belt near the posterior body end, corresponding to the single adhesive girdle. Proboscis symmetric, 145 µm long. Proboscis ( Fig. 9 A–B: pr, 9C) with paired fields of shark-tooth-shaped denticles on each proboscis lip. Toothed belts from both lips separated by a ‘basal gap’. In the basal half of the toothed belts, the denticles are 0.6–1 µm long (x = 0.9 µm; n = 20) and are ordered in five to six rows. In the distal half the teeth are 3–4 µm long (x = 3 µm; n = 26) and are ordered in two to three rows. In live animals, polygonal glands are present on the internal surface of the lips. The largest of the glands are arranged into two rows following the central longitudinal axis of each lip. At both sides of the large glands, smaller glands can be observed. These glands are not observable on the whole mounts. Pharynx ( Fig. 9A : ph) 95 µm in diameter, located at 75%.

A pair of testes is located rostrally from the pharynx. The vasa deferentia ( Fig. 9F : vad) open separately into a single seminal vesicle ( Fig. 9E : sv), which itself opens proximally into the copulatory bulb. Copulatory bulb ( Fig. 9A : cb, 9D–F) 102 µm long and 29 µm at the widest point, without hard structures, ending in a muscular papilla. The prostate vesicle is short and rounded. Two types of prostate secretions were observed in the prostate vesicle of the live animal ( Fig. 9 D–E: pv): in the proximal third a fine-grained secretion and in the middle third a coarsegrained secretion. Distal third of the copulatory bulb muscular, forming a penis papilla ( Fig. 9 D–F: pp).

Paired vitellaria extend between the brain ( Fig. 9A : br) and the copulatory bulb. Ovaries and bursa located caudally from the common gonopore.

Figures

FIGURE 9. Carcharodorhynchus papillaris sp. n.. A, body. B, anterior end of the body. C, proboscis. D–F, copulatory bulb. A–B, E–F, from the live animal. C–D, from the holotype.