Tubifex montanus Kowalewski, 1919

Peng, Yu, Wang, Hongzhu & Cui, Yongde, 2014, Two species of Naididae (Annelida, Clitellata) from southern Tibet, China, ZooKeys 444, pp. 59-68 : 60-62

Taxon classification Animalia Haplotaxida Naididae

Tubifex montanus Kowalewski, 1919 Figs 2, 4; Table 2

Tubifex montanus Kowalewski: Hrabě 1939, 1981; Brinkhurst and Jamieson 1971.

Examined material.

IHB XZ20130630g-i, 2 whole-mounted mature specimens although only 1 specimen has male ducts that can be observed and measured, 1 specimen is used for scanning electron microscopy. Wetland in Cuomujiri Mountain (29°47'46"N, 94°24'53"E) of southern Tibet, China. 30 June 2013, collected by H.Z. Wang, Y.D. Cui, Y.J. He and Y. Peng.

Description.

Length 10-12 mm, width at XI 0.4-0.7 mm. Segments 41-56. Prostomium obtuse. Clitellum inconspicuous. No coelomocytes.

Dorsal chaetae (0)1-3 hairs and 1-3 needles per bundle. Hairs smooth (Fig. 2 H–I), 180-463 µm long. Needles almost palmate (3-11 teeth or more, Fig. 2I and Fig. 4D), 40-100 µm long, two short outer teeth nearly equal (7.5 µm /7.5 µm). Ventral chaetae 60-100 µm long with (0)1-2 fine intermediate teeth partly (Fig. 2 J–L and Fig. 4 A–C), anteriorly 3-4 per bundle with upper tooth slightly thinner than and nearly 2-3 times as long as the lower (7.5 µm /3 µm), in midbody 1-2 per bundle with two nearly equal teeth (5 µm /5 µm), posteriorly 1-2 per bundle with upper tooth nearly 2 to 3 times as long as the lower (5 µm /2 µm). Ventral chaetae in XI present but unmodified.

Pharyngeal glands in II–V. Chloragogen cells beginning in VI onwards. Male ducts paired in X-XI (Fig. 4F). Vas deferens 722 µm long or more, nearly 2.2 times longer than the atrium, uniform and forming numerous loops in XI, ciliated throughout and entering narrow atrium subapically (Fig. 4F, vd). Atrium pear-shaped, with quite long ejaculatory duct, and gradually becomes narrower toward the ectal end, 343 µm long (Fig. 4F, at). Large compact prostate gland empties into the atrial ampulla near the sperm duct outlet, 137 µm long, 83 µm wide (Fig. 4F, pr). Penis cylindrical, 132 µm long, surrounded by a cuticularized, funnel-like penial sheath (Fig. 4E), 172 µm long and 71 µm wide at the ental end. Spermatheca absent. Testes paired in X. Ovaries paired in XI.

Distribution.

Cuomojiri Mountain, southern Tibet of China. A wetland with abundant hydrophytes. Tatra Mountains, Europe ( Hrabě 1939; Brinkhurst and Jamieson 1971).

Remarks.

According to the characteristics of a long vas deferens entering pear-shaped atrium subapically, large compact prostate gland with stalk-like attachments to atrium and penis with funnel-like penial sheath, the species fits the definition of Tubifex Lamarck, 1816 ( Brinkhurst and Jamieson 1971).

The new material resembles Tubifex montanus Kowalewski, 1919 in absence of spermathecae, vas deferens nearly of a similar length with cilia throughout, pear-shaped atrium with quite long ejaculatory duct gradually becoming narrower toward the ectal end, large compact prostate gland empting into the atrial ampullae near the sperm duct outlet, cylindrical penis, surrounded by cuticularized and funnel-like penial sheath, and nearly the same type of dorsal ventral chaetae (Table 2).

However, the new material differs slightly from the description by Hrabě (1939, 1981) by having the vas deferens entering the atrium subapically, straight penis sheath with ental end wider and smooth hair chaetae.