Martiodrilus (Maipure) alexi Bartz & Decaëns, 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 : 219-221

Martiodrilus (Maipure) alexi Bartz & Decaëns , n. sp.

( Fig. 14 )

urn:lsid:zoobank.org:act:6E1A80C3-5EA9-4309-8D46-65175597C61B

TYPE MATERIAL. — Holotype. French Guiana • Adult; Tumuc-Humac, Mitaraka Massif , plateau forest at base camp, in the soil; 2°14’2”N, 54°27’1”W; 331 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0284 ; MNHN.

Paratypes. French Guiana • 2 adult specimens; 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-MI15-0181 , EW-MI15-0195 ; CEFE • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , tropical rainforest on DIADEMA project C trail; 2°14’4”N, 54°26’54”W; 323 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0364 ; MNHN .

ETYMOLOGY. — This species is dedicated to our late friend and colleague Alexander Feijoo-Martínez, who passed away prematurely in December 2023. Alex was a great specialist in Neotropical earthworm taxonomy, and was particularly interested in the genus Martiodrilus , to which the species we are dedicating to him belongs.

ECOLOGY. — Martiodrilus (M.) alexi Bartz & Decaëns , n. sp. has been found essentially in the organo-mineral soil of plateau forest ecosystems ( Fig. 14D, E ).

DISTRIBUTION. — Martiodrilus (M.) alexi Bartz & Decaëns , n. sp. is only known from the Mitaraka Massif.

DESCRIPTION

External morphology ( Fig. 14A, B )

Body shape cylindrical, slightly flattened after clitellum. Body pigmentation dorsally beige to brown, with antero-posterior gradient, ventrally beige. Body length: 225 mm in the holotype, 170 to 197 mm in the paratypes (average: 183.5; n = 2), after ethanol fixation. Body mass: 6.67 g after ethanol fixation in the holotype, 4.63 to 6.38 g in the paratypes (average: 5.5; n = 2). Diameter: 7.5 to 8 mm in the preclitellar region, 9.5 to 10.2 mm in the clitellum, 7.7 to 8.8 mm in the postclitellar region. Number of segments: 139 in the holotype, 149 to 164 in the paratypes (average: 156.5; n = 2). Prostomium proepilobic. Setae closely paired, beginning in II. Setal arrangement aa:ab:bc:cd:dd = 5:1:10:1:28. Clitellum in 1/nXIV-XXV (1/3XXVI), saddle-shaped ( Fig. 14A ). Genital markings variable in V-XIII, intraclitellar in XIV, XVII-XXI in ab. Tubercula pubertatis linear in XX-XXVI ( Fig. 14B ). Male pores not recognised externally, internally open in 20/21, and ovipores not visible. Spermathecal pores in 4/5, 5/6, 6/7 and 7/8. Nephridial pores begining in II, in D line.

Internal anatomy ( Fig. 14C )

Septa: thickened in 9/10 to 14/15, otherwise membranous. Gizzard: muscular and well developed in VI, displaced to X-XI, with an average size (width × length) of 6.37 × 7.40 mm. Calciferous glands: eight pairs in VII-XIV, with XII, XIII and XIV twice larger than the others; gland in VII-IX with kidney shape, otherwise globular to pear-shaped; all with lobular distal appendix and composite tubular structure. Esophagus-intestine transition in XVII/XVIII; intestine without caeca. Typhlosole abruptly begining in XXV/XXVIII, structured as a long thin folded lamella occupying all the lumen. Hearts: five pairs in VII-XI, the two intestinal pairs in X-XI larger and enclosed in testes sacs. Excretory apparatus holoic, nephridia with simple nephrostome. Testes: periesophageal in X and XI, enclosing seminal vesicles, hearts and calciferous glands. Seminal vesicles: two pairs in XI-XII; the first pair extending to X and lobulated in XI; the second pair lobulated extending to XV without perforating septa. Spermathecae: four pairs in V, VI, VII and VIII; elongated with edge lobulated.

REMARKS

Martiodrilus (M.) alexi Bartz & Decaëns , n. sp. belongs to the subgenus Maipure due to the presence of four pairs of spermathecae. It is quite similar to M. (M.) luminescens Decaëns & Bartz , n. sp. and M. (M.) mitaraka Decaëns & Bartz , n. sp. regarding the position of clitellum and tubercula pubertatis ( Table 4 ). It can however be separated from M. (M.) luminescens Decaëns & Bartz , n. sp. by the position of spermathecae (in V-VIII instead of VI-IX), the position of the tubercula pubertatis of one segment more anterior (XX-XXVI instead of XXI-XXVII), and its slightly larger body size (170 to 225 mm instead of 109 to 170 mm). It further differs from M. (M.) mitaraka Decaëns & Bartz , n. sp. by its larger size ( M. (M.) mitaraka Decaëns & Bartz , n. sp. ranging from 100 to 130 mm), its lighter pigmentation, by the presence of thickened septa in 9/10 to 14/15 and the absence of distal appendix in calciferous glands. The three species are clearly separated by their DNA barcodes. Martiodrilus (M.) alexi Bartz & Decaëns , n. sp. is also similar to M. (M.) ophioides which may also have a clitellum in XIV-XXV and has tubercula pubertatis in XX-XXVI. Martiodrilus (M.) alexi Bartz & Decaëns , n. sp. is however much larger in body size than this species (which ranges from 100 to 120 mm), from which it also differs in the position of the spermathecal pores in 4/5- 7/8 instead of 5/6-8/9. Furtheremore, M. (M.) alexi Bartz & Decaëns , n. sp. occurs in a radically different habitat from the Andean forests from which M. (M.) ophioides is known. This species corresponds to OTU#085 in Maggia et al. (2021).

Figures

FIG. 14. — Martiodrilus (Maipure) alexi Bartz & Decaëns 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 position of the tubercula pubertatis); C, dorsal dissection showing anterior internal anatomy; D, habitat preferences;E, microhabitat preferences.All images from the holotype;CL, clitellum; DV, dorsal vessel;GZ, gizzard;IN, intestine;SP, spermathecae;SV, seminal vesicles; TP, tubercula pubertatis; N, total number of specimens in the dataset.