bs_bs_banner Zoological Journal of the Linnean Society, 2012, 166, 530–558. With 10 figures The Parvidrilidae – a diversified groundwater family: description of six new species from southern Europe, and clues for its phylogenetic position within Clitellata (Annelida) Downloaded from https://academic.oup.com/zoolinnean/article-abstract/166/3/530/2629179 by guest on 09 October 2019 ENRIQUE MARTÍNEZ-ANSEMIL1, MICHEL CREUZÉ DES CHÂTELLIERS2, PATRICK MARTIN3* and BEATRICE SAMBUGAR4 1Departamento de Bioloxía Animal, Bioloxía Vexetal e Ecoloxía, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, E-15071 A Coruña, Spain 2Université de Lyon, UMR5023 Ecologie des Hydrosystèmes naturels et anthropisés, Université Lyon 1, ENTPE, CNRS, 6 rue Raphaël Dubois, 69622 Villeurbanne, France 3Institut royal des Sciences naturelles de Belgique, Biologie des Eaux douces, Rue Vautier 29, B-1000 Brussels, Belgium 4Museo Civico di Storia Naturale, Lungadige Porta Vittoria 9, I-37126 Verona, Italy Received 29 November 2011; revised 2 July 2012; accepted for publication 7 July 2012 The Parvidrilidae Erséus, 1999 constitute the most recently described family of oligochaete microdriles. Prior to this study, Parvidrilus strayeri Erséus, 1999, and Parvidrilus spelaeus Martínez-Ansemil, Sambugar & Giani, 2002, found in groundwaters of the USA (Alabama) and Europe (Slovenia and Italy), respectively, were the only two species in this family. In this paper, six new species – Parvidrilus camachoi, Parvidrilus gianii, Parvidrilus jugeti, Parvidrilus meyssonnieri, Parvidrilus stochi, and Parvidrilus tomasini – and Parvidrilus gineti (Juget, 1959) comb. nov. are added to the family. With all species being stygobiont, the Parvidrilidae is unique in being the only family of oligochaetes worldwide comprising taxa that are restricted to groundwater habitats. Parvidrilids are exceedingly small worms whose principal morphological characteristics are the presence of hair setae in ventral bundles, the markedly posterior position of setae within the segments, the presence of mid-dorsal glandular pouches in mesosomial segments, the lateral development of the clitellum, the presence of a single male pore in segment XII, and the presence (or absence) of a single spermatheca. The phylogenetic relationships of the Parvidrilidae within the Clitellata were investigated using the nuclear 18S rRNA gene, and the most representative and taxonomically balanced data set of clitellate families available to date. The data were analysed by parsimony, maximum likelihood, and Bayesian inference. Irrespective of the method used, Parvidrilidae were placed far from Capilloventridae, one family once suggested to be closely related to parvidrilids. Although closer to Enchytraeidae than Phreodrilidae, two other suggested putative sister families, the exact position of Parvidrilidae within Clitellata still remained uncertain in the absence of branch support. The examination of reproductive structures, together with the similarity of other important anatomical traits of the new species herein described, reinforced the idea that phreodrilids were the best candidate to be the sister group to parvidrilids on morphological grounds. A fragment of the mitochondrial cytochrome oxidase I gene, used as a barcode, also genetically characterized a few Parvidrilus species. The observation that two species diverge from each other by high genetic distances, even though their type localities are more or less only 100 km apart, is interpreted in the context of low dispersal abilities of inhabitants of the subterranean aquatic ecosystem, and habitat heterogeneity. The Parvidrilidae appear to be a diversified, Holarctic, and probably widely distributed family in groundwater, but very often overlooked because of the small size and external similarity with the polychaete family Aeolosomatidae of its members. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 530–558. doi: 10.1111/j.1096-3642.2012.00857.x ADDITIONAL KEYWORDS: aquatic oligochaete, molecular systematics, phylogeny. *Corresponding author. E-mail: [email protected] 530 © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 530–558 NEW EUROPEAN SPECIES OF PARVIDRILIDAE 531 INTRODUCTION particularly arrangement, number, and types of setae: absence of setae in segment II (dorsal bundles The Parvidrilidae Erséus, 1999, constitute the most in phreodrilids, dorsal and ventral bundles in capill- recently described family of oligochaete microdriles. oventrids), presence of hair setae in dorsal and Previously, only two species had been described in ventral bundles in capilloventrids, and a similar set of this family – Parvidrilus strayeri Erséus, 1999 from needle and hair setae in the dorsal bundles of phreo- Alabama (USA), and Parvidrilus spelaeus Martínez- drilids and parvidrilids. In parvidrilids, however, Ansemil, Sambugar & Giani, 2002 from Slovenia and dorsal needles emerge from the body wall and do not Italy (southern Europe). Both are exceedingly small look like support setae as in phreodrilids – species in worms (around 1 mm long, 50 mm wide) and were which such setae are always contained within the Downloaded from https://academic.oup.com/zoolinnean/article-abstract/166/3/530/2629179 by guest on 09 October 2019 collected in groundwater environments. setal sac (Pinder & Brinkhurst, 1997). Groundwater habitats are important centres of During this work, we found new specimens of biodiversity, serving as refugia for relictual species P. spelaeus and six new species of Parvidrilus.In (Gibert & Deharveng, 2002). During the last two addition, our re-examination of specimens convinced decades, and especially as a result of the European us that Aeolosoma gineti Juget, 1959, should be trans- Protocols for the Assessment and Conservation of ferred to Parvidrilidae. The availability of so many Aquatic Life in the Subsurface (PASCALIS) project new species for description gave us a morphological (Gibert, 2001; Gibert & Culver, 2009), the study of framework to compare the Parvidrilidae in depth with groundwater oligochaete biodiversity has benefited other oligochaete families. A few specimens of two from a renewed interest from the present authors new Parvidrilus species from France, and of previ- and a few other colleagues. To date, more than 300 ously described P. spelaeus, were suitable for molecu- nominal species have been already found in ground- lar analyses. This additional molecular facet provided waters all over the world, although the present the opportunity to (1) characterize these three species knowledge is almost limited to the karst of southern with a fragment of the mitochondrial cytochrome Europe (Martin et al., 2008; Martínez-Ansemil & oxidase I (COI) gene, used as a barcode; (2) assess the Sambugar, 2010). Some of these species should be genetic divergence between them, and to put these considered as incidentals or waifs – taxa most likely data in a biogeographical context; and (3) investigate carried along by surface waters flowing into sub- the phylogenetic relationships of the Parvidrilidae terranean environments where they were unable to within the Clitellata using the nuclear 18S rRNA sustain viable populations (Creuzé des Châtelliers gene. The accumulation of new data on the distribu- et al., 2009); however, about one third of them have tion and habitat of parvidrilids resulting from this been found exclusively in this environment (stygo- large amount of material has provided us with a bionts; Martin et al., 2008; Creuzé des Châtelliers more comprehensive understanding of the biogeogra- et al., 2009; Martínez-Ansemil & Sambugar, 2010). phy and ecology of this unique family of microdrile The observation of an important species richness oligochaetes. of the marine subfamily Phallodrilinae (Naididae) in groundwaters of southern Europe (B. Sambugar, N. Giani & E. Martínez-Ansemil, 1999; unpubl. data) MATERIAL AND METHODS and the discovery of two new species of the hitherto Baikalian genus Rhyacodriloides Chekanovskaya MORPHOLOGICAL STUDY (Naididae, Rhyacodriloidinae) in subterranean water The material presently studied results from different bodies of the eastern Alps (Martin, Martínez-Ansemil sources: three collecting campaigns in Sardinian & Sambugar, 2010) appear amongst the most out- caves (Italy) organized by our colleague Fabio Stoch, standing discoveries. Phallodrilines and rhyacodri- a study of the groundwater oligochaete fauna of the loidines have also a very small size in common with French Jura, and a large survey of the groundwater parvidrilids, although the latter are even smaller. fauna of six European regions in the course of the As a result of peculiar morphological features, the PASCALIS project (Gibert, 2001; Gibert & Culver, Parvidrilidae is thought likely to be an ancient family, 2009), which enabled us to study material from the and to hold a key phylogenetic position within the Italian Lessinian Mountains, Slovenian Krim Massif, Clitellata and vis-à-vis the Annelida. Each time the and Spanish Cordillera Cantábrica. The PASCALIS systematic position of the Parvidrilidae was discussed sampling protocol was designed to account for habi- on morphological grounds (Erséus, 1999; Martínez- tat heterogeneity, with the primary objective being Ansemil et al., 2002), the attention was focused pri- evaluation of the biodiversity of European groundwa- marily on Capilloventridae and Phreodrilidae as the ter habitats. One advantage