Ilyodrilus mesoprostatus
- Dataset
- Three new species of Tubificinae, Oligochaeta, from two plateau lakes in Southwest China
- Rank
- SPECIES
- Published in
- Cui, Yongde, Wang, Hongzhu (2009): Three new species of Tubificinae, Oligochaeta, from two plateau lakes in Southwest China. Zootaxa 2143: 45-54, DOI: 10.5281/zenodo.188610
Classification
- kingdom
- Animalia
- phylum
- Annelida
- class
- Clitellata
- order
- Enchytraeida
- family
- Randiellidae
- genus
- Ilyodrilus
- species
- Ilyodrilus mesoprostatus
description
Description: Specimen incomplete, length> 4.4 mm, diameter at XI about 0.7 mm, segments> 22. Clitellum inconspicuous. Dorsal chaetae 2 – 5 hairs and 2 – 4 bifids per bundle, hairs slender and smooth, 250 – 350 µm long, 2.0 µm thick basally; bifids (Fig. 4 C) 100 – 125 µm long, 2.5 – 3.0 µm thick, with upper prong longer and thicker than lower. Dorsal chaetae absent in XI. Ventral chaetae (Fig. 4 A – B) bifid, 2 – 4 per bundle, 100 – 120 µm long, 2.5 – 3.0 µm thick, with upper prong longer and thinner than lower. Spermathecal chaetae unmodified in X. Penial chaetae absent in XI. Male pores paired in line with ventral chaetae in mid-XI. Spermathecal pores paired in line with ventral chaetae in mid-X. Pharyngeal glands in II – III. Chloragogen cells from VI onwards. No coelomocytes. Male genitalia (Fig. 4 D) paired. Vas deferens (Fig. 4 D, vd) short and broad, 240 – 360 µm long, 36 – 46 µm wide, entering atrium apically. Atrial ampulla (Fig. 4 D, aa) somewhat spindle-shaped, 280 – 320 µm long, 58 – 108 µm wide. Prostate gland (Fig. 4 D, pr) large, attached to middle portion of atrium by short stalk. Atrial duct (Fig. 4 D, ed) curved, about 54 µm long, 25 – 36 µm wide. Soft part of penis (Fig. 4 D, pe) cylindrical, about 32 µm long, 20 µm diameter, enclosed in copulatory sac; penis surrounded by thin cuticularized, truncated-cone shaped sheath (Fig. 4 D, ps; Fig. 4 E), 116 µm long, 40 – 80 µm wide, one side of the ectal opening (Fig. 4 E, eo) curved upwards. Copulatory sac (Fig. 4 D, cs) 64 µm long, 40 – 50 µm wide. Spermathecal ampullae (Fig. 4 D, sa) oval to round, 105 – 125 µm in diameter, with sperm masses (Fig. 4 D, sm) in lumina, ducts (Fig. 4 D, sd) 160 – 250 µm long, 35 – 58 µm wide.
discussion
Remarks: The genus Ilyodrilus consists of the type species, I. perrieri Eisen, 1879, together with I. templetoni (Southern, 1909) and the dubious entities I. frantzi Brinkhurst, 1965 and I. fragilis Eisen, 1879. The principal characteristics and the distribution of congeners are shown in Table 3.
distribution
Distribution and habitat: Known only from type locality, Yunnan Province, China. Freshwater lake, 5.0 m depth, water temperature 16 ºC, fine silt.
etymology
Etymology: “ meso ” and “ prostatus ” are Latin for “ middle ” and “ prostate ”, respectively. The specific name refers to the prostate glands attaching to the middle part of the atria.
materials_examined
Holotype: IHB YAN 20030405 n, whole-mounted specimen. Type locality: Xingyun Lake (24 ° 18 ' 01 ΄ N, 102 ° 47 ' 58 ΄ E), eastern Yunnan Province, China; depth 5.0 m, bottom temperature 16.1 ° C, dissolved oxygen at bottom 7.6 mg / L, total nitrogen in water 2.960 mg / L, total phosphorus in water 0.129 mg / L, fine silt; 7 Apr 2003, coll. Y. Cui.
Name
- Homonyms
- Ilyodrilus mesoprostatus