Unciherpia hirsuta García-Álvarez, Urgorri & Salvini-Plawen, 2001

Unciherpia hirsuta García-Álvarez, Urgorri & Salvini-Plawen, 2001: 114 .

MATERIAL EXAMINED. — Corsica (France) [4 specimens] • 1 specimen (used for sclerite preparations, histology, and DNA extraction); CORSICABENTHOS 3 (Table 2); 122 m depth;MNHN-IM-2019-18279; GenBank: OQ600031; OQ597875 (1 microscope slide with sclerites, 1 SEM stub; 4 slides with 5 µm serial sections) • 3 specimens (preserved in 95% ethanol); CORSICABENTHOS 3 (Table 2); 122 m depth; MNHN-IM-2019-18282, MNHN-IM-2019-18283, MNHN-IM-2019-18284.

DESCRIPTION

Animals with elongate body (10-15 mm × 0.8-2 mm), without keels or protuberances and with the anterior region wider than the posterior. White to yellow with a strongly hirsute appearance (Fig. 4D). With hollow acicular sclerites: long straight acicular sclerites (200-300 × 5-6 µm) (Fig. 9G); acicular sigmoid sclerites (120-160 × 5-7 µm); straight and long sclerites with harpoon-shaped distal end (360-520 × 8-14 µm) (Fig. 9F); serrated acicular sclerites (230-300 × 8-10 µm) only in the anterior half of the body; and hook-shaped sclerites (150-180 × 7-9 µm) (Fig. 9 H-I). With one type of knife-shaped scales of the pedal groove (75-85 × 12 -14 µm). Mouth opening at the posterior end of the atrial cavity. Without radula. With 16 circum-pharyngeal subepithelial follicular glands (Fig. 14A).

REMARKS

Within Pruvotinidae, the subfamily Unciherpiinae García-Álvarez, Urgorri & Salvini-Plawen, 2001 is characterized by the absence of a radula and by having circum-pharyngeal follicular glands instead of ventrolateral foregut glands (García-Álvarez et al. 2001; García-Álvarez & Salvini-Plawen 2007; Pedrouzo et al. 2022) (Table 4). The three genera in this subfamily, all of which are represented by a single described species, can be differentiated based on the sclerites. Uncimenia Nierstrasz, 1903 and Unciherpia have harpoon-shaped and hook-shaped sclerites, but the hook-shaped sclerites lack an apical prominence in Uncimenia . Sialoherpia Salvini-Plawen, 1978 lacks hook-shaped sclerites and has solid, acicular sclerites (Salvini-Plawen 1978; García-Álvarez et al. 2001). The specimen from Corsica was identified as Unciherpia hirsuta based on the external aspect and sclerites (García-Álvarez et al. 2001: fig. 1; Pedrouzo et al. 2014: fig. 2). In addition, this identification was confirmed by the study of the internal anatomy: common atrio-buccal cavity, 16 follicular glands surrounding the pharynx (Fig. 14A), midgut with a short, paired rostral caecum, respiratory folds and one dorso-terminal sensory organ (García-Álvarez et al. 2001; Pedrouzo et al. 2014).

The known geographical distribution of U. hirsuta includes several localities near the type locality (NW Iberian Peninsula) (García-Álvarez et al. 2001; Pedrouzo et al. 2019) and the Alboran Sea (Mediterranean Sea) (Pedrouzo et al. 2014). The Atlantic specimens were found at depths between 760 and 1499 m (García-Álvarez et al. 2001; Pedrouzo et al. 2014) while the specimen collected in the Alboran Sea was found at a greater depth (349-365 m) (Pedrouzo et al. 2014). The specimens from Corsica were collected at 122 m in sandy bottoms, which corresponds in terms of habitat with previous localities in which the species was found (García-Álvarez et al. 2014).