Enchytraeus demutatus sp. nov. (Enchytraeidae, Oligochaeta) has characters hitherto unrecorded in the genus

  • Rüdiger M. Schmelz IfAB Institute of Applied Soil Biology, Tomberg 24a, 22337 Hamburg, Germany; University of A Coruña, Science Faculty, GIBE, Evolutionary Biology Group, CICA, Centro de Investigaciones Científicas Avanzadas, As Carballeiras s/n, Campus de Elviña, 15071 A Coruña, Spain
  • Mårten J. Klinth Department of Biological & Environmental Sciences, University of Gothenburg, P.O. Box 463, SE-405 30 Gothenburg, Sweden
  • Christina Chalkia Agricultural University of Athens, School of Plant Sciences, Faculty of Crop Science, Laboratory of Agricultural Zoology and Entomology, 75 Iera Odos, 11855 Athens, Greece
  • Pelagia Anastasiadou Benaki Phytopathological Institue, 8 Stefanou Delta str., 14561 Kifissa, Greece
  • Evangelia Vavoulidou Soil Science Institute of Athens, 1 S. Venizelou str, 14123 Likovrisi, Attikis
Keywords: Clitellata, soil fauna, soil biodiversity, taxonomy

Abstract

A new species of enchytraeids with peculiar characters is described, Enchytraeus demutatus sp. nov. The species differs from all known species of Enchytraeus in features of the oesophageal appendages and the male efferent apparati. The oesophageal appendages insert ventro-laterally below the pharyngeal pad and not dorsally behind the pad, as is usual in the genus; furthermore, their histology is different. The male efferent apparati have each an unusually wide and short vas deferens, and accessory glands are attached to the inner surface of the male glandular bulb, in close vicinity to the male pore. The remaining characters agree with the genus diagnosis of Enchytraeus, notably the presence of testis sacs and oesophageal appendages. The bisetose worms are about 5 mm long and 0.2–0.3 mm wide. The peculiarities of the oesophageal appendages raised the possibility to place the species in a new genus. DNA sequencing was performed to provide molecular identifiers and to assess the generic placement of the species. The molecular phylogenetic analysis, based on a concatenation of the six genetic markers 12S, 16S, 18S, 28S, COI and H3 placed E. demutatus inside the well-supported (PP  =  0.99) Enchytraeus clade and not outside, hence the new species is to be considered a member of Enchytraeus. The tree includes species that cover a wide range of the morphological diversity in Enchytraeus; here E. demutatus sp. nov. groups with a sub-branch that includes the other bisetose species, also the fragmenting ones, but also one species with 3 chaetae per bundle; whereas species of the E. buchholzi-group and the E. albidus-group, respectively, form clades of their own. E. demutatus sp. nov. was found in soil samples derived from a tomato field of a private greenhouse farm in the regional division of Ilia, West Greece, together with abundant E. bigeminus.

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Published
2019-12-01
How to Cite
Schmelz, R. M., Klinth, M. J., Chalkia, C., Anastasiadou, P., & Vavoulidou, E. (2019). Enchytraeus demutatus sp. nov. (Enchytraeidae, Oligochaeta) has characters hitherto unrecorded in the genus. SOIL ORGANISMS, 91(3), 87–96. https://doi.org/10.25674/so91iss3pp87
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