Neogaster csuzdii 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 : 225-228

Neogaster csuzdii Bartz & Decaëns , n. sp.

( Fig. 17 )

urn:lsid:zoobank.org:act:E45DE917-168A-44C4-8374-1DAA3D857F34

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-MI15-0205 ; MNHN.

Paratypes. French Guiana • 1 adult specimen; Tumuc-Humac, Mitaraka Massif , lowland forest on DIADEMA project D trail; 2°13’58”N, 54°27’7”W; 318 m a.s.l.; III.2015; T. Decaëns, E. Lapied leg.; BOLD Sample ID: EW-MI15-0304 ; CEFE • 1 adult specimen; 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-MI15-0344 ; MNHN .

ETYMOLOGY. — This species is named in homage to Csaba Csuzdi, in recognition for his involvement in the study of the Benhamiidae family, and his contribution to the description of new earthworm species for French Guiana.

ECOLOGY. — The three known specimens of N. csuzdii Bartz & Decaëns , n. sp. have been found in a lowland, a slope and a transition forests ( Fig. 17C ), two in decaying trunks and one in the litter accumulating on a granite rock ( Fig. 17D ).

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

DESCRIPTION

External morphology ( Fig. 17A, B )

Body shape cylindrical, slightly flattened posteriously. Body pigmentation dorsally light yellow-brown, lighter ventrally.Body length: 20 mm in the holotype, 30 mm in one paratype, after ethanol fixation. Body mass: 0.02 g after ethanol fixation in the holotype, 0.04 g in the paratype. Diameter: 1.3 to 1.5 mm in the preclitellar region, 1.4 to 1.9 mm in the clitellum, 1.7 to 1.9 mm in the postclitellar region. Number of segments: 79 in the holotype to 99 in the paratype. Prostomium tanylobic.

Species Pigmentation Size (mm) Clitellum Tubercula pubertatis Calciferous glands Spermathecae Testes Andiorrhinus pascalei Bartz & Decaëns, n. sp. Absent 158 to 196 (dorsal XIII) XIV-XXI (dorsal XXII-XXIII) 1/ XV-3/ XX 4 4 Three pairs in VII-IX, lamellar structure Three pairs in VII-IX, very small spatula-shaped Two pairs of testes and funnels in X -XI Martiodrilus flavus Decaëns & Bartz, n. sp. Yellow to grey, clitellum pink 265 to 300 (½ XIII) XIV- ½ XXVI XIX-XXV Eight pairs in VII-XIV, tubular composite structure Three pairs in VI-VIII, small elongated Midventral or hypoesophagic in X-XI Martiodrilus tchoukouchipan Decaëns & Bartz, n. sp. Dorsally yellow-brown, ventrally yellow 55 to 75 (dorsal XIV) XV (XVI)- ½ XXV 1/4XX-3/4 XXV Eight pairs in VII-XIV, tubular composite structure Three pairs in VI-VIII, elongated Periesophageal in X-XI, enclosing SV Martiodrilus pavliceki Bartz & Decaëns, n. sp. Dorsally yellow-brown to brown, ventrally beige 95 (dorsal XIV) XV-XXV (dorsal XXVI) XIX-1/nXXV Eight pairs in VII-XIV, tubular composite structure Three pairs in VII-IX, thin duct terminated by a round and flattened sac Periesophageal in X-XI, enclosing SV, heart and CG Martiodrilus lavellei Decaëns & Bartz, n. sp. Dorsally light brown, ventrally beige 56 (dorsal XV) XVI-XXV 1/ XX-½ XXV 4 Eight pairs in VII-XIV, tubular composite structure Three pairs in VI-VIII, ovoid elongated Periesophageal in X-XI, enclosing SV, heart and CG Martiodrilus mitaraka Dorsally red- 100 to 130 (dorsal ½ XIII, XIV) XV (XVI)- XXV (XIX) XX-(XXV) XXVI Eight pairs in VII-XIV, tubular composite structure Four pairs in V-VIII, elongated Periesophageal in X-XI Martiodrilus luminescens Decaëns & Bartz, n. sp. Dorsal grey-brown, ventral light brown 109 to 170 (XIV) ½ XV-XXVI XXI-XXVII Eight pairs in VII-XIV, tubular composite structure Four pairs in VI-IX, elongated Periesophageal in X-XI, sacs attached in XIV/ XV Martiodrilus wayana Bartz & Decaëns, n. sp. Dorsally dark brown, ventrally yellow 55 to 74 (dorsal XIII, XIV) XV-(XXV) XXVI XX- ½ XXVI Eight pairs in VII-XIV, tubular composite structure Three pairs in VI-VIII, spatula-shaped Periesophageal in X-XI, enclosing SV Martiodrilus alexi Bartz & Decaëns, n. sp. Dorsally beige to brown, ventrally beige 170 to 225 1/n XIV-XXV (1/ XXVI) 3 XX-XXVI Eight pairs in VII-XIV, tubular composite structure Four pairs in V-VIII, elongated Periesophageal in X-XI, enclosing SV, heart and CG Martiodrilus motoloi Bartz & Decaëns, n. sp. Dorsally dark red-brown, ventrally light brown 42 to 56 (dorsal XIV) XV- ½ XXVI 1/3XX-½ XXV Eight pairs in VII-XIV, tubular composite structure Three pairs in VI-VIII, elongated Periesophageal in X-XI, enclosing SV, heart and CG Urobenus gui a nomeridionalis Bartz & Decaëns, n. sp. Dorsally dark grey, ventrally beige to yellow 35 to 41 XV-XXIV 1/4XIX (½ XIX)- XXIII Three pairs, tubular paniculated structure in VII-VIII and trabecular structure in IX Three pairs in VII-IX, small elongated Two pairs in X and XII Atatina albida Bartz & Decaëns, n. sp. Absent 25 to 41 XV-XXIV XVII-XXIV Four pairs intestinal, intra-mural in IX-XII Two pairs in VIII and IX Midventral metandric in XI

Decaëns & Bartz, n. sp. brown, ventrally

light brown

Dorsal pores begining in 5/6. Setae closely paired, beginning in II, ab ventral and cd sub-ventral. Setal arrangement aa:ab:bc:cd = 4:2:4:1, dd> ½ Ø. Clitellum in XIII-XX, annular. Genital markings: paired papillae in VIII to XII (bc position), intraclitellar in XIII to XVI (ab position); acanthodriline male field forming an ovoid depression in XVII-XX. A pair of ventral male pores in XVIII, and ovipores not visible. 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-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 meronephridial with two pairs of nephridia per segment. Prostatic glands: two pairs in XVII and XIX, elongated lingulate. Ovaries: one pair in XIII. Testes: two pairs of testes sacs in X and XI. Seminal vesicles: one pair in XII, small. Spermathecae: one pair in IX, sac-shaped without diverticulum.

REMARKS

Neogaster csuzdii Bartz & Decaëns , n. sp. is closely related to Neogaster tumuchumac Decaëns & Bartz , n. sp. with which it shares small body size, the absence of a gizzard and the entirely membranous septa in the anterior part of the body ( Table 5 ). It is distinguished from all other Neogaster by the presence of a single pair of spermathecae in IX, whereas the other species have two (in N. tumuchumac Decaëns & Bartz , n. sp.), three (in Neogaster angeloi Righi, 1988 and Neogaster americanus Cernosvitov, 1934 ), four (in Neogaster gavrilovi Righi & Caballero, 1970 ) or five (in Neogaster aidae Righi, 1975 ). In N. csuzdii Bartz & Decaëns , n. sp., we observed only one pair of seminal vesicles in XII, whereas two pairs are usually present in other species except in N. aidae in which no seminal vesicle has been seen (but see remarks on N. tumuchumac Decaëns & Bartz , n. sp.). Neogaster csuzdii Bartz & Decaëns , n. sp. is smaller than most of the other species (20-30 mm compared to over 40 mm in N. americanus , N. aidae and N. gavrilovi ), and differs from the equally small N. angeloi by the presence of skin pigmentation, which the latter lacks ( Cernosvitov 1934; Righi & Caballero 1970; Righi 1975, 1988). Neogaster csuzdii Bartz & Decaëns , n. sp. is clearly separated from N. tumuchumac Decaëns & Bartz , n. sp. from its COI barcode ( Table 3 ). This species corresponds to OTU#009 in Maggia et al. (2021).

Figures

FIG. 17. — Neogaster csuzdii 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 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.