Carcharodorhynchus smilodon Diez & Reygel & Artois 2019, sp. n.

Carcharodorhynchus smilodon sp. n.

(Fig. 8)

http://zoobank.org/ urn:lsid:zoobank.org:act: 4A 200176 -9D9C-49CF-865D-F56B95ACADD3

Material. One specimen studied alive and whole mounted, designated holotype (FMNH https://id.luomus.fi/ KV.613), from Siboney (type locality) (December 9, 2017), sublittoral, medium-grained clean sand, 4 m depth, salinity 33 ‰.

Etymology. The epithet refers to the extinct Saber-tooth tigers Smilodon spp. (Mammalia), as the new species has some large denticles on the proboscis.

Diagnosis. Species of Carcharodorhynchus with symmetric proboscis, lips 127 µm long. The belts of denticles show a ‘basal gap’; denticles shark-tooth shaped, 2 µm long in the basal half of the belts, ordered in four rows, and 5 µm long in the distal half, ordered in a single row. Spiny cirrus 33 µm long.

Description. Live animal about 2 mm long, yellowish, caudally dark yellow-brownish, without eyes. There is a pale belt near the posterior body end, corresponding to the single adhesive girdle. Proboscis lips symmetric, 127 µm long. Proboscis (Fig. 8A: pr, 8B–C) with paired fields of shark-tooth-shaped denticles, situated on a belt on each proboscis lip. Denticles at the base of the proboscis separated by a ‘basal gap’. In the basal half of the toothed belts, the denticles are 1–2 µm long (x = 2 µm; n = 17) and are ordered in four to five rows. More distally there is only one row of 4–6-µm-long denticles (x = 5 µm; n = 12). 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 133 µm in diameter, located at 60%.

Testes not observed. A pair of elongated seminal vesicles open proximally into the copulatory bulb. Copulatory bulb (Fig. 8 D–E) 162 µm long, with the same construction as that of C. flavidus; it comprises the very large prostate vesicle (Fig. 8 D–E: pv) and the spiny cirrus. Spiny cirrus (Fig. 8 D–F: ci) 33 µm long, proximally 9 µm wide and distally 16 µm wide, with the same morphology as that of C. flavidus , including the detailed morphology and dimensions of the spines (see Brunet 1967).

Paired vitellaria extend between the brain (Fig. 8A: br) and the copulatory bulb. Bursa and ovaries (Fig. 8 E–F: ov) are situated just caudally from the copulatory bulb. A single oocyte was observed in each ovary.