Allolobophora delitescens Gérard, Decaëns & Marchán, 2023

Gérard, Sylvain, Marchán, Daniel Fernández, Navarro, Alejandro Martinez, Hedde, Mickaël & Decaëns, Thibaud, 2023, Resampling Bouché’s historical localities reveals three new species and helps identifying a new genus of earthworms (Oligochaeta, Hormogastridae and Lumbricidae) in Southeastern France, Zoosystema 45 (23), pp. 749-768 : 757-758

Allolobophora delitescens Gérard, Decaëns & Marchán , n. sp.

( Figs 6 ; 7 )

urn:lsid:zoobank.org:act:85A16708-ADFF-4E67-AE80-B317E0E19FDD

TYPE MATERIAL. — Holotype. France • 1 adult specimen; Provence-Alpes-Côte d’Azur, Var, 83830 Callas, in the soil; 43°34’22”N, 6°31’48”E; 305 m a.s.l.; 28.XI.2021; T. Decaëns, D. F. Marchán, S. Gérard, R. Della Vedova leg.; MNHN ( BOLD Sample ID: SG-0024 ).

Paratypes. France • 1 adult specimen; same data as holotype; Eco & Sols ( BOLD Sample ID: SG-0046 ) • 1 sub-adult specimen; MNHN ( BOLD Sample ID: SG-0047 ).

ETYMOLOGY. — The species name is derived from the present participle of the latin verb delitesco, is, ere, which can be translated to the intransitive verb “to hide”. This is a reference to the fact that Marcel Bouché did not find this species despite his sampling in 1968 at the type locality.

ECOLOGY. — A. delitescens Gérard, Decaëns & Marchán , n. sp. was found in a Mediterranean grassland, previously an olive tree orchard, surrounded by pine forests, at a low elevation (305 m a.s.l.).

DISTRIBUTION. — A. delitescens Gérard, Decaëns & Marchán , n. sp. is only known from its type locality, near the city of Callas, in the sedimentary basin north to the Esterel massif in the Var department (Provence-Alpes-Côte d’Azur, France) ( Fig. 5 ).

DESCRIPTION

External morphology ( Fig. 6A, B )

Body shape cylindrical. Body pigmentation absent. Average body length after ethanol fixation: 85 mm (range: 72 to 98 mm; n = 2 adult specimens; holotype: 98 mm). Average body mass: 0.918 g (range: 0.639 to 1.197 g; n = 2; holotype: 1.197 g). Average diameter in the preclitellar region: 4.7 mm (range: 4.6 to 4.7 mm; n = 2; holotype: 4.7 mm), 5.0 mm in the clitellum (range: 4.9 to 5.0 mm; n = 2: holotype: 5.0 mm), 4.5 mm in the postclitellar region (range: 4.1 to 4.8 mm; n = 2; holotype: 4.8 mm). Average number of segments: 201 (range: 200 to 202; n = 2; holotype: 202; 1 subadult specimen with 211 segments). Prostomium of closed epilobous type. Setae closely paired. Setal arrangement aa:ab:bc:cd:dd = 11:1:6:1:29. Clitellum in (XXXV) XXXVI–(XLVI) XLVII. Genital markings in intraclitellar in XXXVII–(XXXVIII) XXXIX. Tubercula pubertatis: thin band in XL-XLVI. Male pores: one pair in XV. Ovipores: one pair in 1/2 XIV, at 1 × ab dorsally from b. Spermathecal pores not visible. Nephridial pores not visible.

Internal anatomy ( Figs 6C ; 7 )

Septa: thickened from 6/7 to 10/11, otherwise membranous. Crop in XV-XVI. Muscular gizzard in XVII-XVIII, followed by a membranous pouch in XIX, with an average size (width × length) of 3.80 × 2.25 mm. Calciferous glands: in X-XIV, forming two kidney-shaped lobes in X. OEsophagus-intestine transition in XV. Typhlosole start in XIX, forming five lamellae. Hearts: in VI-XI. Excretory apparatus: one pair of holonephridia per segment, nephridial vesicles U-shaped ( Fig. 7 ). Seminal vesicles: four pairs in IX-XII, smaller in IXX, large lobulated in XI-XII. Spermathecae: three pairs in 8/9, 9/10, 10/11, small globular and intraseptal, simple (a single case of a double spermathecae).

REMARKS

Allolobophora delitescens Gérard, Decaëns & Marchán , n. sp. can be distinguished from its closest relatives A. icterica and A. dubiosa by the position of the clitellum and tubercula pubertatis, by the type of typhlosole, and by the absence of pigmentation and the smaller size in the latter case ( Table 4 ).

Figures

FIG. 6. — Allolobophora delitescens Gérard, Decaëns & Marchán, n. sp.: A, external view of the anterior body; B, lateral view of the anterior body; C, dissection of the anterior body. Abbreviations: CL, clitellum, CR, crop, GM, genital marks, GZ, gizzard, IN, intestine, MP, male pore, SEP, septa, SV, seminal vesicles, TP, tubercula pubertatis, TY, typhlosole. Scale bars: 5 mm. Photos: T. Decaëns.

FIG. 7. — Pre-clitellar nephridia of Allolobophora delitescens Gérard,Decaëns & Marchán, n. sp. Scale bar: 1 mm. Photo: D. F. Marchán.

FIG. 5. — Distribution of newly described Lumbricidae species, Flabellodrilus luberonensis Gérard, Decaëns & Marchán, n. gen., n. sp. and Allolobophora delitescens Gérard, Decaëns & Marchán, n. sp. (stars), and their closest relatives (circles) in Southern France. All species within the genus Flabellodrilus Gérard, Decaëns & Marchán, n. gen. are represented. Credits: Google 2022.