Martiodrilus (Maipure) luminescens 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 : 215-217

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

( Fig. 12 )

urn:lsid:zoobank.org:act:C0B6F2F4-F011-4CE0-B842-3D05A0D4CA27

TYPE MATERIAL. — Holotype. French Guiana • Adult; Tumuc-Humac, Mitaraka Massif , rocky savannah #2 on Sommet en Cloche Inselberg , in terrestrial bromeliad roots; 2°13’58”N, 54°27’39”W; 427 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0319 ; MNHN.

Paratypes. French Guiana • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , rocky savannah #2 on Sommet en Cloche Inselberg ; 2°13’58”N, 54°27’39”W; 427 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0318 ; CEFE • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , slope forest on DIADEMA project D trail; 2°13’40”N, 54°27’14”W; 339 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0254 ; CEFE • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , slope forest on trail to Sommet en Cloche Inselberg ; 2°14’6”N, 54°27’11”W; 351 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0194 ; MNHN .

OTHER MATERIAL EXAMINED. — French Guiana • 2 juvenile specimens; Tumuc-Humac, Mitaraka Massif , rocky savannah #2 on Sommet en Cloche Inselberg ; 2°13’58”N, 54°27’39”W; 427 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0329 , EW-MI15-0330 ; MNHN • 2 juvenile specimens; 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-MI15-0202 , EW-MI15-0209 ; MNHN • 3 juvenile specimens, 1 cocoon; Tumuc-Humac, Mitaraka Massif , slope forest on DIADEMA project D trail; 2°13’40”N, 54°27’14”W; 339 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0263 , EW-MI15-0264 , EW-MI15-0269 , EW-MI15-0276 ; MNHN • 4 juvenile specimens; Tumuc-Humac, Mitaraka Massif , transition forest # 1 Sommet en Cloche Inselberg ; 2°13’54”N, 54°27’39”W; 401 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0337 , EW-MI15-0339 , EW-MI15-0340 , EW-MI15-0376 ; MNHN • 1 juvenile specimen; Tumuc-Humac, Mitaraka Massif , tropical rainforest on crowned mountain; unknown; unknown; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0132 ; MNHN .

ETYMOLOGY. — The name of the species refers to the bioluminescent character observed on one of the type specimens during field sampling.

ECOLOGY. — Martiodrilus (M.) luminescens Decaëns & Bartz , n. sp. has been found mostly in slope forests (41.18% of specimens) and in inselberg rocky savannahs (23.53%) and transition forests (23.53 ( Fig. 12F ). Most specimens were collected in decaying trunks (35.29%), in litter accumulations on granite rocks (23.53%) and in the root mat of terrestrial bromeliads (23.53%) ( Fig. 12G ). Cocoons are tan yellow, spherical, 10 mm in diameter, with two mucrons at the anterior and posterior ends. A specimen moving at night on the surface of the ground was observed producing a green bioluminescence.

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

DESCRIPTION

External morphology ( Fig. 12A, B )

Body shape cylindrical, slightly flattened after clitellum. Body pigmentation dorsal grey-brown, ventral light-brown. Body length: 109 mm in the holotype, 105 to 170 mm in the paratypes (average: 139 mm; n = 3), after ethanol fixation. Body mass: 1.87 after ethanol fixation in the holotype, 1.84 to 5.38 g in the paratypes (average: 3.90 g; n = 3). Diameter: 5.3 to 7 mm in the preclitellar region, 9 to 10.3 mm in the clitellum, 6.5 to 8 mm in the postclitellar region. Number of segments: 108 in the holotype, 85 to 136 in the paratypes (average: 118.3; n = 3). Prostomium proepilobic. Setae closely paired, ab and bc beginning in IV. Setal arrangement aa:ab:bc:cd:dd = 7:1:14:1:42. Clitellum in (XIV) ½ XV-XXVI, saddle-shaped ( Fig. 12A ). Genital markings in in V-IX, intraclitellar in XVI, XIX and XXIV (ab position). Tubercula pubertatis linear in XXI-XXVII ( Fig. 12B ). Male pores not recognised, and ovipores not visible. Spermathecal pores invisible. Nephridial pores begining in II, in CD line.

Internal anatomy ( Fig. 12 C-E)

Septa: membranous. Gizzard: muscular and well developed in VI, but displaced to X, XI and XII, with an average size (width × length) of 4.27 × 5.40 mm. Calciferous glands: eight pairs in VII-XIV, yellow bean-shaped with a brown round distal appendix, and composite tubular structure ( Fig. 12E ). Esophagus-intestine transition in XVII; intestine without caeca. Typhlosole absent. Hearts: six pairs, the two intestinal pairs in X-XI well developed and enclosed in the testes sacs. Excretory apparatus holoic, nephridia with simple nephrostome.Testes sacs: periesophageal in X and XI, but sac enclosing calciferous glands, heart and seminal vesicles. Seminal vesicles: two pairs in XI and XII-XVI, lobulated ( Fig. 12E ). Spermathecae: four pairs, VI, VII, VIII and IX, without diverticula ( Fig. 12D ).

REMARKS

Martiodrilus (M.) luminescens Decaëns & Bartz , n. sp. belongs to the subgenus Maipure due to the presence of four pairs of spermathecae. It is related to other species sharing a clitellum in XV-XXVI, such as Martiodrilus (Maipure) micrurus Cognetti de Martiis, 1904 , Martiodrilus (Maipure) potarensis Rosa, 1895 , Martiodrilus (Maipure) ophioides ( Cognetti de Martiis, 1904) and Martiodrilus (Maipure) rigeophilus Cognetti de Martiis, 1904 . It differs from the first two species in the position of the tubercula pubertatis in XXI-XXVII instead of ½ XX-½ XXV in M. (M.) Micrurus, XXI-XXVI in M. (M.) potarensis, XX-XXVI in M. (M.) ophioides and XX-½ XXVI in M. (M.) rigeophilus . Martiodrilus (M.) luminescens Decaëns & Bartz , n. sp. is also significantly smaller than M. (M.) potarensis (109-170 mm instead of 380 mm), and larger than M. (M.) rigeophilus and M. (M.) ophioides which have body sizes ranging from 70 to 80 mm and from 100 to 120 mm, respectively. Furthermore, both of these two last species are known from high-altitude montane ecosystems (above 4000 and 2500 m a.s.l., respectively) which are quite different from the type habitat in which M. (M.) luminescens Decaëns & Bartz , n. sp. was found. This species corresponds to OTU#082 in Maggia et al. (2021).

Figures

FIG. 12. — Martiodrilus (Maipure) luminescens 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 position of the tubercula pubertatis);C, dorsal dissection showing anterior internal anatomy; D, detail of the anterior part of the dorsal dissection showing the spermathecae; E, detail of the dorsal dissection showing the seminal vesicle and the calciferous glands; F, habitat preferences; G, microhabitat preferences. All images from the holotype; CL, clitellum; CG, calciferous glands; DV, dorsal vessel; GZ, gizzard; HT, intestinal hearts;IN, intestine;SP, spermathecae;SV, seminal vesicles;TP, tubercula pubertatis;N, total number of specimens in the dataset.Scale bars:10 mm.