Dendrobaena hortensis (Michaelsen, 1890)

D. hortensis View in CoL group

A separate clade on the tree (Fig. 1) was formed by D. veneta , D. hortensis , and a putative new species from the Western Caucasus. The affinity between D. veneta and D. hortensis was supported in other studies ( Csuzdi & Zicsi, 2003; Kvavadze, 1985). Briones et al. (2009) remarked that D. veneta and D. hortensis are similar in the position of the clitellum and tuberculae pubertatis, chromosome number, and by the absence of diverticules of the calciferous gland in the 10th segment. However, at the same time, they differ in the distance between the setae, the number of spermathecae, and the morphology of the typhlosole, body size, and ecological preferences.

The prospective new species found in the eastern Caucasus could not be assigned to any existing species within Dendrobaena . Its clitellum starts on the 27th segment, as in D. alpina , D. veneta , and D. hortensis , and ends on 32nd, as in D. schmidti . The position and shape of the tuberculae pubertatis are also similar to D. schmidti . The new species is frequently found under the bark of fallen trees in the arid Eastern Caucasus, just like D. veneta . Dendrobaena sp. probably belongs to the “ alpina ” rather than the “ veneta ” group due to the presence of large calciferous diverticulae in the 11th segment (C. Csuzdi, personal communication). The affinity of Dendrobaena sp. to D. veneta and D. hortensis confirms the complexities that arise during phylogenetic reconstructions.

This group clustered together with a specimen identified as Dendrodriloides grandis . The genus Dendrodriloides was isolated by Kvavadze (2000) from the genus Eisenia , primarily in the form of the genital setae, as well as the position of the locomotor setae and spermathecae. Species of Dendrodriloides and the closely related genus Dendrobaena typically exhibit similar muscle types and nephridial morphology ( Kvavadze, 2000; Zhgenti et al., 2006).