Tegulaherpia cf. myodoryata Salvini-Plawen, 1988

Cobo, M. Carmen, Farris, William J. & Kocot, Kevin M., 2024, New data on the biodiversity of Solenogastres (Mollusca, Aplacophora) in the Mediterranean Sea: findings from the program “ Our Planet Reviewed ” Corsica 2019 - 2022, Zoosystema 46 (21), pp. 543-576 : 558

Tegulaherpia cf. myodoryata Salvini-Plawen, 1988

Tegulaherpia myodoryata Salvini-Plawen, 1988: 377 .

MATERIAL EXAMINED. — Corsica (France) • 1 specimen (preserved in 95% ethanol in two pieces, middle region used for sclerite preparations and DNA extraction); CORSICABENTHOS 1 ( Table 2 ); 41 m depth; MNHN-IM-2019-16176; GenBank: OR456213 (1 microscope slide with sclerites, and tissue in ethanol).

DESCRIPTION

Small (3.8 × 0.4-1 mm) bright white animal, anterior end wider than the posterior ( Fig. 4A , A’). Light brown color in the midgut region when alive ( Fig. 4 A’). With imbricate oval scales (30-40 × 20-25 µm) ( Fig. 7E ). Knife-like scales around the pedal groove (40 × 28 µm). With a small pallial cavity opening visible externally in the live specimen in which a protruding copulatory stylet was also observed.

REMARKS

The family Lepidomeniidae includes three genera that differ essentially, following the existent classification, in the shape of the sclerites ( Kowalevsky 1883; Kowalevsky & Marion 1887; Heath 1918; Salvini-Plawen 1983; García-Álvarez et al. 2000; Salvini-Plawen2003): Lepidomenia Kowalesky, 1883 with triangular scales; Nierstrazia Heath, 1918 with leaf-shaped scales and Tegulaherpia Salvini-Plawen, 1983 with oval scales ( Kowalevsky 1883; Heath 1918; Salvini-Plawen 1983). In addition, Lepidomenia hystrix Marion & Kowalevsky, 1885 lacks copulatory stylets ( Kowalevsky & Marion 1887), thus the lack of this structure is included in the diagnosis of the genus ( García-Álvarez & Salvini-Plawen 2007), as they exist in the other two genera. The Corsica specimen has oval scales and copulatory stylets. Based on this, it was placed in the genus Tegulaherpia . The identification of the specimen from Corsica as Tegulaherpia cf. myodoryata is justified by the external similarities (color, size and sclerites) of the examined specimen to published data on this species ( Salvini-Plawen 1988; Handl & Salvini-Plawen 2001: fig. 13) and the sclerites. The scales of the Corsica specimen correspond, in shape and size, with those described for Tegulaherpia myodoryata ( Handl & Salvini-Plawen 2001: 17; Salvini-Plawen 2003: fig. 7). Tegulaherpia includes another Mediterranean species, T. stimulosa Salvini-Plawen, 1983 that can be differentiated from T. myodoryata based on the sclerites: more oval in T. myodoryata ( Salvini-Plawen 1988; Salvini-Plawen 2003). Nevertheless, a study of the internal anatomy, especially the posterior organs, is important for confident identification. Due to the small size of the available specimen, we discarded histology, as a genus-level identification was adequate for the aims of this study. Moreover, the distinction between the genera in Lepidomeniidae is most likely in need of revision (personal observations) for which the analysis of the diagnostic characters, including a thorough and updated description of the sclerites of all the species is necessary.

T. myodoryata has been recorded from the Mediterranean (Banyuls-sur-Mer and Livorno) and the North Atlantic Ocean ( Norway and Irish Sea). If the identification of the specimen from Corsica is confirmed, the distribution of this species would be extended to the Mediterranean Sea and the minimum depth at which it can be found would be decreased from 70 to 40 m. As with previous findings of T. myodoryata ( García-Álvarez et al. 2014) , the specimen from Corsica was collected from a sandy bottom.

Figures

FIG. 4. — Habitus of A, Tegulaherpia cf. myodoryata (photo of the living animal – MNHN-IM-2019-16176); A’, Tegulaherpia cf. myodoryata (photo of the preserved specimen – MNHN-IM-2019-16176); B, Eleutheromenia sierra (Pruvot, 1890) (photo of the preserved specimen – MNHN-IM-2019-1749); C, Pruvotia cf. sopita (photo of the preserved specimen – MNHN-IM-2019-1744 – on Sertularella sp.); D, Unciherpia hirsuta García-Alvarez, Urgorri & Salvini-Plawen, 2001 (photo of the living animal – MNHN-IM-2019-18279); E, Simrothiella margaritacea (Koren & Danielssen,1877) (photo of the preserved specimen – MNHN-IM-2019-18280). Scale bars 1 mm. Symbols: arrow, copulatory stylets; stars, anterior end of the animals.

FIG. 7. — SEM images of the sclerites of A-D, Nematomenia banyulensis (Pruvot, 1890) (MNHN-IM-2019-1747); E, Tegulaherpia cf. myodoryata (MNHN- IM-2019-16176); F, Simrothiella margaritacea (Koren & Danielssen,1877) (MNHN-IM-2019-18280); G, H, Dorymenia vagans (Kowalevsky & Marion,1887) (MNHN- IM-2019-18274); I, Anamenia gorgonophila (Kowalevsky, 1880) (MNHN-IM-2019-18270). Scale bars: 20 µm.