Eutyphoeus dhubriensis, Ahmed & Julka & Banerjee & Marimuthu, 2023

Ahmed, Shakoor, Julka, Jatinder Mohan, Banerjee, Dhriti & Marimuthu, Nithyanandam, 2023, A new species of the genus Eutyphoeus Michaelsen 1900 (Clitellata: Acanthodrilidae) from the North-Eastern Biogeographic Zone, India, Zootaxa 5380 (2), pp. 167-172 : 168-169

Eutyphoeus dhubriensis sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:1A6C2DB9-2DF6-41BF-BC37-2A5D9114CBCB

( Figs 1 & 2 )

Material examined. Holotype: Clitellate (ZSI-GNC-An7271/1), India, Assam, Dhubri, near Dheer beel (26° 17' 17.3544"N; 90° 23' 27.456"E); 37 m above mean sea level; 23 August 2022; leg. Shakoor Ahmed. Paratypes: 04 clitellate (ZSI-GNC-An7272/1), collection details same as for Holotype.

Etymology. The species is named after the district Dhubri from where the specimens were collected.

Diagnosis. Length 66–95mm, Width 3–3.5mm. Segments 108–188, 7&8 biannulate, 9–12 triannulate. Color light brown. First dorsal pore 11/12. Clitellum 131/2 – 17, dorsal pores absent, setae present. Avestibulate, male pores open in oval porophores in segment 17 at ab. Spermathecal pores in 7/8 center at b slight extended toward median. Female pores paired, presetal on segment 14, at a setal line. Genital markings paired at ab, post setal on segments 12 and 18. Spermathecae bidiverticulate, lateral (anterior directed) and median (posterior directed). Metandric, seminal vesicles in 12 extend to segment 14. Prostates tubular, extending from segments 17 to 20 or 21, duct 1.5– 2mm long. Lateral intestinal caecae absent, median and ventral caecae, small, finger like, 4–5 in segments 29–34. Supra–intestinal glands 3–4 pairs in segments 67–71. Typhlosole simple, lamelliform, ending at or before the beginning of supra-intestinal glands. Dorsal blood vessel complete extending anterior to segment 4. Penial setae straight, cylindrical, pointed ental end. Genital marking glands sessile, circular.

Description. Holotype. Small size worm; length 67 mm; width 3.5mm at clitellum. Body cylindrical, segments119; segment 7 and 8 biannulate, 9–12 slightly triannulate. Prostomium tanylobic ( Fig. 1B ). Preserved specimens light brown. First dorsal pore in intersegmental furrow 11/12. Setae present on segment 2, lumbricine, closely paired; aa:ab:bc:cd:dd = 2:1:2:1.5:6.25 at segment 10, aa:ab:bc:cd:dd = 2.5:0.8:1.25:1:6.5 at segment 20. Clitellum annular, on segments 131/2 –17. Female pores paired, presetal at a setal line on segment 14. Spermathecal pores in intersegmental furrow 7/8 center at b slight extended toward median. Male genital region avestibulate (without deep aperture), pores discharging through oval porophores at ab ( Fig. 1A ). Genital markings paired, post setal on segment 12 and 18 at ab ( Fig. 1A ). Penial setae present.

Septa 4/5/6 and 8/9/10 thickened, 10/11–12/13 slightly thickened, 6/7/8 absent. Oesophagus gizzard, single in space between 5/6–7/8. Intestine begining in segment 15. Typhlosole simple, lamelliform begin in segment 25. Lateral typhlosole absent. Supra-intestinal glands 4 pairs in segments 67–70 ( Fig. 2D ). Lateral caecae absent, ventral caecae small finger-like, median 5 in segments 30–34 ( Fig. 2C ). Nephridia Meronephric. Calciferous glands intramural, paired in segment 12. Last pair of hearts in segment 13. Dorsal blood vessel complete extend anterior to gizzard in segment 4. Metandric, testis and funnels in segment 11, seminal vesicles in segment 12 extending posterior to segment 14 ( Fig. 2A ). Prostates coiled, tubular, extending from segment 17 to 20, duct wavy, 2mm long ( Fig. 2A ). Ovaries and funnels in segment 13. Spermathecal duct short, ampulla ovoid, large; bidiverticulate, lateral (anterior directed) and median (posterior directed) opening separately slightly above the junction of duct and ampulla ( Fig. 2B ). Genital marking glands sessile, circular, associated with each marking. Penial setae 4 per battery, with length, 1.5–2mm; and 45.5–49µm thick, little spiny ornamentation, rounded with pointed tip ( Fig. 1C, D ).

Remarks. The new species belongs to a group of avestibulate, metandric species, with bidiverticulate spermathecae, lacking lateral intestinal caecae. It showed closed relationships with the Indian species Eutyphoeus assamensis Stephenson, 1926 , E. comillahnus Michaelsen, 1907 , E. festivus Gates, 1938 and E. scutarius Michaelsen, 1907 (Table 1). The new species distinguished from all these in location of supra-intestinal glands and the location of genital markings. Further, the genital markings are paired in new species, which are unpaired in E. comillahnus , E. festivus and E. scutarius . The new species has sessile genital marking glands which are absent in E. assamensis , E. comillahnus and E. scutarius . Furthermore, the new species conforms with E. festivus in having sessile genital marking glands but is distinguished concerning characters mentioned above as well as in length, the position of median ventral intestinal caecae and shape of penial setae, tip spoon-shaped in E. festivus rather than rounded in E. dhubriensis sp. nov. (Table 1).

Figures

FIGURE 1. Eutyphoeus dhubriensis sp. nov. A. ventral view, B. prostomium, C&D. penial setae (gm, genital markings; mp, male pores; ps, penial setae; spp, spermathecal pores).

FIGURE 2. Eutyphoeus dhubriensis sp. nov. A. internal anatomy, B. spermathecae, C. Ventral intestinal caecae, D. supraintestinal glands. (am, ampulla; di, diverticulum; gi, gizzard; ic, intestinal caecae; mg, genital marking glands; pg, prostate glands; si, supra-intestinal glands; sv, seminal vesicles; ts, testis).