Omodeoscolex tetraspermatheca 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 : 233-235

Omodeoscolex tetraspermatheca Decaëns & Bartz , n. sp.

( Fig. 21 )

urn:lsid:zoobank.org:act:ECE72D9E-C9DB-48FC-B69C-A4676C1DE816

TYPE MATERIAL. — Holotype. French Guiana • Adult; Tumuc-Humac, Mitaraka Massif , slope forest on DIADEMA project A trail, in decaying trunk; 2°14’16”N, 54°27’7”W; 344 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0203 ; MNHN.

Paratypes. French Guiana • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , slope forest on DIADEMA project A trail; 2°14’16”N, 54°27’7”W; 344 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0204 ; CEFE .

ETYMOLOGY. — The species name refers to the presence of four unpaired spermathecae.

ECOLOGY. — The two known specimens of O. tetraspermatheca Decaëns & Bartz , n. sp. have been collected in a decaying trunk in a slope forest ( Fig. 21C, D ).

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

DESCRIPTION

External morphology ( Fig. 21A, B )

Body shape cylindrical, slightly flattened posteriously. Body pigmentation dorsally reddish-brown, ventrally light yellow-brown. Body length: 18 mm in the holotype, 26 mm in the paratype, after ethanol fixation. Body mass: 0.04 g after ethanol fixation in the holotype, same in the paratype. Diameter: 1.6 to 1.8 mm in the preclitellar region, 1.5 to 2.6 mm in the clitellum, 1.4 to 2.5 mm in the postclitellar region. Number of segments: 117 in the holotype, 122 in the paratype. Prostomium tanylobic. Dorsal pore: begining in 4/5. Setae closely paired, beginning in II, ab ventral and cd sub-ventral. Setal arrangement aa:ab:bc:cd = 5:1:5:1, dd> ½ Ø. Clitellum in XIII-XX, annular. Genital markings in two transversal lips in 3/4XVI and 1/4XX, delimiting a rectangular acanthodriline male field. Male pores one ventral pair in XVIII, and ovipores one pair in XIV, presetal, internally diagonal to a. Spermathecal pores not visible. Nephridial pores in line of C.

Internal anatomy

Septa: membranous. Gizzard: absent. Calciferous glands: two pairs in XIV and XV, with lamellar structure, kidney-shaped and attached through the middle inside. Esophagus-intestine transition in XVI. Typhlosole absent. Hearts: five pairs, last three intestinal bigger and last pair in XII. Excretory apparatus holoic. Prostatic glands: two pairs in XVII and XIX, irregular lobulated shape. Ovaries: one pair in XIII, grape bunch-shaped. Testes: two pairs in X and XI. Seminal vesicles: one pair, very small in XII, attached to septum 11/12. Spermathecae: four unpaired midventral in VI to IX, roundball-sac-shaped.

REMARKS

Omodeoscolex tetraspermatheca Decaëns & Bartz , n. sp. is characterized by the presence of four unpaired spermathecae in VI-IX, whereas in the other known species of the genus with unpaired spermathecae there are three ( O. touroulti Decaëns & Bartz , n. sp. and O. abamaensis Bartz & Decaëns , n. sp.) ( Table 5 ). It also differs from the two previously described species by its COI-barcode ( Table 3 ). This species corresponds to OTU#086 in Maggia et al. (2021).

Figures

FIG. 21. — Omodeoscolex tetraspermatheca 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.