Scherotheca darioi Marchán, Decäens & Domínguez, 2023

Marchán, Daniel Fernández, Domínguez, Jorge, Hedde, Mickaël & Decaëns, Thibaud, 2023, The cradle of giants: insights into the origin of Scherotheca Bouché, 1972 (Lumbricidae, Crassiclitellata) with the descriptions of eight new species from Corsica, France, Zoosystema 45 (3), pp. 107-128 : 114-116

Scherotheca darioi Marchán, Decäens & Domínguez , n. sp.

( Fig. 3C )

urn:lsid:zoobank.org:act:ACEE54C6-DECC-47DC-B0E1-013B83518F75

TYPE MATERIAL. — Holotype. Corsica • Adult; Haute-Corse, Murato, Cagnanozza ; 42°33’39”N, 9°18’14”E; 715 m a.s.l.; 1.IV.2021; T. Decaëns, D. Fernández Marchán leg.; BOLD Sample ID: DFM-0393 ; MNHN.

Paratypes. Corsica • 2 adult specimens; Haute-Corse, Murato; 42°34’12”N, 9°18’21”E; 536 m a.s.l.; 1.IV.2021; T. Decaëns , D. Fernández Marchán leg.; BOLD Sample ID: DFM-0401, DFM-0402; MNHN • 4 adult specimens; Haute-Corse, Murato, Cagnanozza; latitude/longitude, 42°33’39”N, 9°18’14”E; elevation, 715 m a.s.l.; 1.IV.2021; T. Decaëns , D. Fernández Marchán leg.; BOLD Sample ID: DFM-0391, DFM-0392, DFM-0393, DFM-0394, DFM-0395; MNHN • 1 adult specimen, 1 juvenile specimen; Haute-Corse, Volpajola; 42°30’54”N, 9°20’52”E; elevation, 313 m a.s.l.; 1.IV.2021; T. Decaëns , D. Fernández Marchán leg.; BOLD Sample ID: DFM-0143, DFM-0150; MNHN • 2 adult specimens; same data as for preceding; BOLD Sample ID: DFM-0148, DFM-0149; Eco&Sols .

ETYMOLOGY. — This species is named in honour of Prof. Darío J. Díaz Cosín, renowned earthworm taxonomist and mentor of several earthworm researchers including the first author of this paper.

DIAGNOSIS. — Scherotheca darioi Marchán, Decäens & Domínguez , n. sp. can be distinguished from non-Corsican species of Scherotheca by the shorter and more anterior clitellum. It resembles Sc. marceli Marchán, Decäens & Domínguez , n. sp., Sc. portonana and Sc. portcrosana , but differs from Sc. marceli Marchán, Decäens & Domínguez , n. sp. in the average length, number of segments, weight and position of the genital papillae; it also differs from Sc. portonana and Sc. portcrosana by the smaller average length, number of segments and weight, the position of genital papillae, and a lighter pigmentation ( Tables 1 ; 2 ; Figs 2 ; 3C ).

COI uncorrected average pairwise distances and topology of multilocus molecular phylogenetic trees support the status of Scherotheca darioi Marchán, Decäens & Domínguez , n. sp. as an independent species from other morphologically similar species.

DISTRIBUTION AND ECOLOGY. — Scherotheca darioi Marchán, Decäens & Domínguez , n. sp. was found in the regions of Murato and Volpajola, Haute Corse ( Fig. 4A ), in Mediterranean chaparral, Quercus suber open wood and ripicolous grasslands, indicating a remarkable ecological plasticity.

DESCRIPTION

External morphology

Body pigmentation faint brown. Beige with white-beige clitellum in fixed specimens ( Fig. 3C ). Average length 75 mm (65-85 mm, n = 6 adults); body cylindrical in cross-section; average number of segments 169 (159-178, n = 5 adults; 168 segments in the holotype). Average weight (fixed specimens), 1 g (0.76-1.25 g, n = 6 adults). Prostomium epilobous, closed. Longitudinal furrows in segments 1 and 2. First dorsal pore in intersegmental furrow 9/10. Nephridial pores “en solfège” (irregularly distributed). Spermathecal pores in intersegmental furrows 12/13 and 13/ 14 in setal line c. Male pores in segment 15, surrounded by a well-developed porophore. Female pores in segment 14. Clitellum saddle-shaped in segments 26-35. Tubercula pubertatis in segments 29-33. Chaetae small and closely paired. Genital papillae in segments 10-(14)16,27,28,34,35(36).

Internal anatomy

Septa 5/6-10/11 thickened and muscular. Hearts in segments 6-11, oesophageal. Calciferous glands in segments 10-14, with diverticula in segment 10. Crop in segments 15-16, gizzard in segments 17-19. Typhlosole pinnate. Male sexual system holandric, testes and funnels (not enclosed in testes sacs, but with sperm present) located ventrally in segments 10 and 11. Four pairs of reniform seminal vesicles in segments 9, 10, 11 and 12, with the latter two pairs being larger. Ovaries and female funnels in segment 13, ovarian receptacles (ovisacs) in segment 14. Two pairs of small globular spermathecae in segments 12 and 13 (intersegments 12/13, 13/14). Nephridial bladders U-shaped, reclinate in segment 30.

REMARK

This species corresponds to Sc. portonana L 2 in the checklist of Corsican earthworms of Marchán et al. (2022a).

Figures

FIG. 3. — External morphology of the newly described species of Corsican Scherotheca Bouché,1972:A, Scherotheca altarocca Marchán,Decäens & Domínguez, n. sp.; B, Scherotheca marceli Marchán, Decäens & Domínguez, n. sp.; C, Scherotheca darioi Marchán, Decäens & Domínguez, n. sp.; D, Scherotheca boccaverghju Marchán, Decäens & Domínguez, n. sp.; E, Scherotheca qiui Marchán, Decäens & Domínguez, n. sp.; F, Scherotheca litoralis Marchán, Decäens & Domínguez, n. sp.; G, Scherotheca capcorsana Marchán, Decäens & Domínguez, n. sp.; H, Scherotheca mausoleana Marchán, Decäens & Domínguez, n. sp. Left side, lateral view; right side, ventral view. Scale bars: 1 cm.

FIG. 2. — External and internal morphological differences between the newly described species of Corsican Scherotheca Bouché,1972 and their closest relatives. The three different shades represent absent, slight and moderate pigmentation. Open circles represent structures that only appear in some individuals. Structures shown in light and dark shades (genital papillae, clitellum and tubercula pubertatis) represent the maximum and minimum extension of these characters, respectively. Phylogenetic relationships are the same as those shown in Figure 1.

FIG. 4. — Distribution of the genus Scherotheca Bouché, 1972 in Corsica: A, localities documented in this work of the newly described species and other Scherotheca species sampled during this work; B, distribution of Corsican species of Scherotheca and Eumenescolex Qiu & Bouché, 1998 according to Bouché (1972), Qiu & Bouché (1998) and Szederjesi et al. (2021).