Pseudolepetodrilus, Betters & Cortés & Cordes, 2024

Betters, Melissa J., Cortés, Jorge & Cordes, Erik E., 2024, New species and records of limpets (Mollusca, Gastropoda) from the Pacific Costa Rica Margin, ZooKeys 1214, pp. 281-324 : 281-324

Pseudolepetodrilus gen. nov.

Fig. 9

Type species.

Pseudolepetodrilus costaricensis sp. nov.

Diagnosis.

Pseudolepetodrilus gen. nov. have a complete shell with fine radial and concentric sculptures, penis originating at the right side of the head, and three pairs of posterior epipodial tentacles.

Description.

Shell (Fig. 9 G, H ): Specimens exhibit patelliform shells with moderate elevation. Apex of shell is located at the posterior end of the shell. Fine concentric radial sculpturing and axial sculpturing present. The aperture and shell margin are ovate and unornamented. Shell is robust with a thick, greenish brown periostracum covering the outer shell and wrapping over the aperture lip.

Soft parts (Fig. 9 I, M ): One pair of short cephalic tentacles are located on the head. One pair of epipodial tentacles are located approximately midway down the foot, with one tentacle present on either side of the organism. Three pairs of epipodial tentacles are present at the posterior end of the organism. These posterior tentacles are short and thin; They do not extend past the shell margin. A thick, triangular penis extends from beneath the right cephalic tentacle. Mouth is V-shaped. Oral lappets are lacking.

Radula (Fig. 9 N, O ): Radula is rhipidoglossate in configuration and is symmetrical. Rachidian tooth is sharp and triangular, lacking denticles. One broad, major lateral tooth on either side of the rachidian flanked by four minor lateral teeth all with triangular cusps: Numerous (15 +) marginal teeth flank the minor lateral teeth on either side, each exhibiting spatulate cusps with short denticles.

Remarks.

Pseudolepetodrilus gen. nov. have a complete shell, penis originating at the right side of the head, and three pairs of posterior epipodial tentacles. Lepetodrilus have a complete shell, penis originating at the right side of the head, and two pairs of posterior epipodial tentacles. Gorgoleptis have a complete shell, penis originating from the left side of the head, and two pairs of posterior epipodial tentacles. Clypeosectus McLean, 1989 has a slit shell and three pairs of posterior epipodial tentacles. Pseudorimula McLean, 1989 has a slit shell and four pairs of posterior epipodial tentacles.

The radulae of this new genus most closely resembles that of Lepetodrilus in that they both have a broad, oblique, first major lateral followed by laterals that rise to a peak at the third tooth and then descend away from the short, triangular rachidian. However, while the major laterals of Lepetodrilus have variable, irregular edges, the major lateral teeth of Pseudolepetodrilus gen. nov. have an even, outer slope without any notches or grooves.

Etymology.

The generic name means false (pseudo) Lepetodrilus , given its close physical resemblance to species of the genus Lepetodrilus .

Figures

Figure 9. Specimens of Lepetodrilus guaymasensis and Pseudolepetodrilus costaricensis gen. et sp. nov. A – C sequenced L. guaymasensis specimen (GenBank Accession # OQ 644591) from Mound 12, 998 m, AD 4917, 1 June 2017 D – F additional L. guaymasensis specimen from Jaco Scar, 1,811 m, AD 4912, 27 May 2017 G – I Pseudolepetodrilus costaricensis sp. nov. holotype (G – I) and sequenced specimen (J – L) (GenBank Accession # OQ 644586), both from tubeworms, Jaco Scar, 1,760 m, AD 4989, 4 November 2018 M close up view of P. costaricensis epipodial tentacles, with tracing N – P radula morphology representative of this new genus O isolated marginal lateral tooth. Scale bars: 1 mm (A – M); 300 µm (N); 50 µm (O); 30 µm (P).