Omodeoscolex touroulti Decaëns & Bartz, 2024

Decaëns, Thibaud, Bartz, Marie Luise Carolina, Bartz, arolina, Feijoo-Martínez, Alexander, Goulpeau, Arnaud, Lapied, Emmanuel, Marchán, Daniel F., Maggia, Marie-Eugénie, Papuga, Guillaume & James, Samuel W., 2024, Earthworms (Oligochaeta, Clitellata) of the Mitaraka range (French Guiana): commented checklist with description of one genus and eighteen species new to science, Zoosystema 46 (9), pp. 196-244 : 231

Omodeoscolex touroulti Decaëns & Bartz , n. sp.

( Fig. 19 )

urn:lsid:zoobank.org:act:7B7FC13C-8E11-411F-9047-3FCFFC7A0EC4

TYPE MATERIAL. — Holotype. French Guiana • Adult; Tumuc-Humac, Mitaraka Massif , lowland forest on DIADEMA project A trail, in termite nest; 2°14’34”N, 54°27’54”W; 327 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0235 ; MNHN.

Paratypes. French Guiana • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , plateau forest at base camp; 2°14’2”N, 54°27’1”W; 331 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0282 ; CEFE • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , slope forest on DIADEMA project C trail; 2°14’5”N, 54°26’42”W; 377 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0079 ; MNHN .

ETYMOLOGY. — This species is named in acknowledgment to Julien Touroult, co-organisator of the “Our Planet Reviewed” in the Mitaraka Massif.

ECOLOGY. — The three specimens of O. touroulti Decaëns & Bartz , n. sp. were found in decaying trunks and termite nest in a lowland, a slope and a plateau forest ( Fig. 19C, D ).

DISTRIBUTION. — Omodeoscolex touroulti Decaëns & Bartz , n. sp. is only known from the Mitaraka Massif.

DESCRIPTION

External morphology ( Fig. 19A, B )

Body shape cylindrical, slightly flattened posteriously. Body pigmentation dorsally reddish-brown, ventrally light yellow-brown. Body length: 25 mm in the holotype, 18 mm one paratype, after ethanol fixation.Body mass: 0.04 g after ethanol fixation in the holotype, 0.015 g in the paratype. Diameter: 1.2 to 1.5 mm in the preclitellar region, 1.3 to 1.6 mm in the clitellum, 1.2 to 1.5 mm in the postclitellar region. Number of segments: 92 in the holotype, 86 in the paratype. Prostomium tanylobic. Dorsal pores begining in 4/5. Setae closely paired, beginning in II, ab ventral and cd sub-ventral. Setal arrangement aa:ab:bc:cd = 4:1:4:1, dd> ½ Ø. Clitellum in XIII-XX, annular. Genital markings in two transversal lips in XVII and XX, delimiting a rectangular acanthodriline male field.One pair of ventral male pores in XVIII, and ovipores one pair in XIV. Spermathecal pores not visible. Nephridial pores not visible.

Internal anatomy

Septa: membranous. Gizzard: absent. Calciferous glands: two pairs in XIV and XV, with lamellar structure, kidney shape and attached through the middle inside part. Esophagus-intestine transition in XVI. Typhlosole weak. Hearts: five pairs, last three intestinal bigger and last pair in XII. Excretory apparatus holoic. Prostatic glands: two pairs in XVII and XIX, spatula-shaped. Ovaries: one pair in XIII, grape-shaped. Testes: two pairs of testes sacs in X and XI. Seminal vesicles: two pairs in XI and XII, very small and weak. Spermathecae: three unpaired midventral in VI to VIII, spherical.

REMARKS

O. touroulti Decaëns & Bartz , n. sp. is different from the two previously described species of Omodeoscolex by the presence of unpaired instead of paired spermathecae. Despite this strong difference, we provisionally assign the species to the genus Omodeoscolex because of lack of a gizzard and of the holonepridial type of its excretory system. This species corresponds to OTU#012 in Maggia et al. (2021).

Figures

FIG. 19. — Omodeoscolex touroulti Decaëns & Bartz n. sp.: A, external and lateral view of the anterior body (arrows indicate the clitellum position); B, external and ventral view of the anterior body (arrows indicate the clitellum male field); C, habitat preferences;D, microhabitat preferences. All images from the holotype; CL, clitellum; MF, male field; N, total number of specimens in the dataset. Scale bars: 1 mm.