A morphological reappraisal of Tubifex blanchardi Vejdovský, 1891 (Clitellata: Tubificidae)

Abstract

Marotta, R., Crottini, A., Prada, V. and Ferraguti, M. 2009. A morphological reappraisal of Tubifex blanchardi Vejdovsk ¥ , 1891 (Clitellata: Tubificidae). -Acta Zoologica (Stockholm) 90 : 179-188Tubifex blanchardi Vejdovsk ¥ , 1891 is a freshwater tubificid, often living in sympatry with Tubifex tubifex (Müller 1774). Although considered from its discovery as a species on its own, its biological status is debated. During the early seventies T. blanchardi was reduced to a mere form of T. tubifex , as a particular case of polymorphism in chaetal pattern. Using classical histological techniques, microdissections of portions of the male genital apparatus and phalloidin staining of dissected copulatory organs we investigated 163 mixed individuals of T. blanchardi and T. tubifex belonging to sympatric populations from the Lambro River (Milan, Northern Italy). The internal morphology of T. blanchardi is described for the first time. Our results show that T. tubifex and T. blanchardi differ in several characters concerning both their external and internal morphology, and in the fine organization of their copulatory organs. Several independent character sets support the separation of T. blanchardi from T. tubifex , suggesting that it is an independent species. This study also supports the idea that T. blanchardi and T. berg i (Hrab ´ , 1935), another species closely related to T. tubifex , are not conspecific. The observed morphological differences between allopatric populations of T. tubifex are discussed.

The Aquatic Oligochaeta (Annelida) Fauna of the Karasu Stream

“…blanchardi is a freshwater tubificid, often occurring together with T. tubifex (Marotta et al 2009). It has a large tolerance range and can live in various habitats (Yıldız 2003).…”

“…It has a large tolerance range and can live in various habitats (Yıldız 2003). In certain conditions, pH, salinity, mercury and hardness concentrations make stress on T. tubifex specimens and induce a gradial loss of hair and pectinate setae thus generating individuals similar to "blanchi" form (Marotta et al 2009). …”

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“…pH was another effective variable on benthic macroinvertebrates and maybe one of its discriminative effect was on T. blanchardi, which is a sympatric species with T. tubifex. In certain conditions, pH, salinity, mercury and hardness concentrations make stress on T. tubifex specimens and induce a gradual loss of hair and pectinate setae, thus generating individuals similar to "blanchi" form (Marotta, Crottini, Prada & Ferraguti, 2009). pH levels are also effective on Chironomidean larvae.…”

Four Unrecorded Species of Tubificid Oligochaetes (Annelida: Clitellata) in Korea

“…Until recently, T. blanchardi was regarded as an ecological form of T. tubifex (Brinkhurst and Jamieson, 1971). Tubifex tubifex has hair chaeta and pectinate, but T. blanchardi only have bifid chaetae in the dorsal chaetal bundles (Marotta et al, 2009). These external morphological differences enabled us to discriminate this species from T. tubifex, although male reproductive organs are similar in these species.…”