Cognettia Nielsen & Christensen 1959

• Main Author: Martinsson, Svante
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2019
• Subjects: Biodiversity; Taxonomy; Animalia; Annelida; Clitellata; Enchytraeida; Enchytraeidae; Cognettia; Greenland; Tundra
• Online Access: https://doi.org/10.5281/zenodo.10870952; http://treatment.plazi.org/id/760F87FCFFF3B56A4181A2DABB4E823B

3. Key to the species of Cognettia 1. 1-2 enlarged chaetae in lateral bundles of 2-3 segments within III-VII. 2 - No enlarged chaetae. 3 2. 2 enlarged chaetae per bundle, spermatheca with ectal gland and ampulla divided into two chambers (see Fig. 1D). C. cognettii (Issel, 1905) The enlarged chaetae are not mentioned as such in the original description, but the length range of chaetae given include them (see Schmelz & Collado 2010). The position of the enlarged chaetae are somewhat variable, they have been observed in III-V or IV-VI in material from the former Yugoslavia (Cernosvitov 1945), in V-VII in material from Britain (Cernosvitov 1945), in IV-VI or V-VII in material from Germany (Römbke 1989), and in V-VII in material from Scandinavia (pers. obs.). The species is distributed widely in Europe. - 1 enlarged chaeta per bundle, spermatheca without ectal gland, and ampulla not divided into two chambers. C. hayachinensis Nakamura, 2001 So far only found in Japan. 3. At least 3 chaetae in all bundles. 4 - All or some bundles with two chaetae.10 4 .Somebundleswith4chaetae. C. quadrosetosa Christensen and Dózsa-Farkas, 1999 An Arctic species, recorded from the Siberian tundra and N Greenland. - 3 chaetae in all bundles. 5 5 . With well-developed secondary pharyngeal glands (see Fig 1A). 6 - Without secondary pharyngeal glands, but ventral lobes may be present (see Fig 1B). 9 6 . Dorsal blood vessel arises in X, spermathecal duct without ectal swelling, but ectal gland well-developed (see Fig. 1D). C. lapponica Nurminen, 1965 An Artic species, recorded widely from the N Palaearctic region. - Dorsal blood vessel arises in XIV, spermathecal duct with or without ectal swelling. 7 7. Spermathecal duct without ectal swelling, ectal gland well developed. 3 pairs of pharyngeal glands, the two posteriormost with well-developed secondary glands, first pair of nephridia at 6/7, male pores in XII. C. zicsii Dózsa-Farkas, 1989 A South American species, known from the Ecuadorian Andes. - Spermathecal duct with ectal ...