Filogeografía, filogenia y especiación críptica en los Hormogastridae

Hormogastridae Michaelsen, 1900 es una familia de lombrices de tierra endémica del Mediterráneo Occidental con 32 especies y subespecies descritas de tamaños mediano agigante. Mientras que su biología y ecología son poco conocidos, sus relaciones filogenéticas han recibido una atención significativa en la última década. Empleando técnicas moleculares, los trabajos de Novo y colaboradores alrededor de 2010 destacaron la necesidad de una revisión sistemática de la familia debido a la no-monofilia de subgénero principal Hormogaster, y también descubrió la diversidad críptica de la morfoespecie H. elisae. Esta tesis identifica las principales cuestiones abiertas por los trabajos anteriormente mencionados, y propone nuevas aproximaciones conceptuales y metodológicas para incrementar nuestro conocimiento del grupo.En el Capítulo II se describe una nueva especie (Hormogaster joseantonioi):su posición filogenética como taxón hermano del complejo Hormogaster elisae matiza el aislamiento geográfico de esta última en el centro de la Península Ibérica y esclarece la posible ruta de colonización de su área de distribución actual. Esta especie mostró también combinaciones de caracteres internas desconocidas previamente, ampliando nuestra comprensión de la diversidad morfológica en hormogástridos..

Macroecological inferences on soil fauna through comparative niche modeling: The case of Hormogastridae (Annelida, Oligochaeta)

Ecological Niche Modeling (ENM) through MaxEnt and quantitative comparison techniques using ENMtools could facilitate ecological inferences in problematic soil dwelling taxa. Despite its ecological relevance in the Western Mediterranean basin, the ecology of the endemic family Hormogastridae (Annelida, Oligochaeta) is poorly known. Applying this comparative approach to the main clades of Hormogastridae would allow a better understanding of their ecological preferences and differences. One hundred twenty-four occurrence data belonging to four clades within this earthworm family were used as input to infer separate MaxEnt models, including seven predictor variables. Niche breadth, niche overlap and identity tests were calculated in ENMtools; a spatial Principal Components Analysis (sPCA) was performed to contrast with the realized niches. The highly suitable predicted ranges varied in their ability to reflect the known distribution of the clades. The different analyses pointed towards different ecological preferences and significant ecological divergence in the four above-mentioned clades. These results are an example of wide-scale ecological inferences for soil fauna made possible by this promising methodology, and show how ecological characterization of relevant taxonomic units could be a useful support for systematic revisions

Evaluating the conservation status of a North-Western Iberian earthworm (Compostelandrilus cyaneus) with insight into its genetic diversity and ecological preferences

In spite of the high conservation value of soil fauna, the evaluation of their conservation status has usually been neglected. This is more evident for earthworms, one of the most important ecosystem service providers in temperate habitats but rarely the subject of conservation research. These studies have not been developed in Western Europe, which comprises high diversity and several early-branching, relic genera. One potentially menaced representative of this fauna is Compostelandrilus cyaneus; this risk can be assessed by implementing potential distribution modeling and genetic diversity monitoring to their known populations. Genetic barcoding was performed in representatives of four populations (three of them newly sampled) in order to estimate genetic diversity and population genetics parameters. Ensemble species distribution models were built by combining several algorithms and using the five more relevant bioclimatic and soil variables as predictors. A large amount of genetic diversity was found in a small area of less than 20 km2, with populations located in less managed, better-preserved habitats showing higher genetic variability than populations isolated from natural habitats and surrounded by anthropic habitats. Potential distribution appears to be strongly restricted at a regional scale, and suitable habitats within the extent of occurrence appear fragmented and relatively limited. In addition, the main variables determining the ecological niche of C. cyaneus suggests a vulnerability to climate change and increasing soil compaction. Based on this knowledge, this species was assessed as Critically Endangered following the IUCN Red List of Threatened Species criteria, and some potential conservation actions are suggested.Ministerio de Ciencia, Innovación y Universidades | Ref. PGC2018-095851-B-C66Ministerio de Ciencia, Innovación y Universidades | Ref. FJCI-2017-32895Xunta de Galicia | Ref. ED431B 2019/03

New light into the hormogastrid riddle: morphological and molecular description of Hormogaster joseantonioi sp. n. (Annelida, Clitellata, Hormogastridae)

The earthworm family Hormogastridae shows a remarkable disjunction in its distribution in the Iberian Peninsula, with the Hormogaster elisae species complex isolated from the rest of the species. Hormogaster joseantonioi sp. n., a new species found in the intermediate area between the main ranges (in Teruel, Aragón), was described following the integrative approach, as it is suitable for earthworms due to their highly homoplasic morphology. The phylogenetic analysis of the molecular markers placed the new species as a sister taxon to H. elisae, thus showing the colonizing lineage of Central Iberian Peninsula could have originated near the H. joseantonioi sp. n. current range. External morphological characters revealed some degree of overlap with previously described species, but internal characters presented configurations/states unknown from other members of the family. These traits make the new species a key piece to understand the evolution of Hormogastridae

Cryptic characters for cryptic taxa: On the taxonomic utility of the genital chaetae in earthworms (Oligochaeta, Hormogastridae)

Hard anatomical characters have successfully been used in invertebrate systematics. Besides their chaetae, this kind of characters is virtually absent from earthworms (a taxonomically challenging group). This work explores the taxonomic utility of genital chaetae, which have been demonstrated to play an important role in earthworm reproduction. Genital chaetae were collected from different clades in the family Hormogastridae, some of them comprising cryptic complexes. The morphology of these structures was studied in detail with scanning electron microscopy and differential interference contrast microscopy with the aim of finding relevant phylogenetic information at different levels: putative diagnostic characters for clades, phylogenetic relationships between clades, and support for cryptic species delimitation. Our results revealed wide morphological variability in the distal tip of the genital chaetae between the different clades (summarized in five qualitative characters) and cryptic lineages. Canonical Variate Analysis based on dorsal landmarks was able to separate chaetae from the cryptic lineages in non-overlapping clusters and Discriminant Function Analysis allowed to assess its reliability. Some complex structures in the tip of genital chaetae, such as denticles and pores, highlighted the necessity of further research on their role in the reproduction of the different earthworm families. Our results support the potential of genital chaetae as a systematic character to resolve conflicting phylogenetic relationships of earthworms, being also potentially suitable for disentangling cryptic species complexes.Ministerio de Ciencia e Innovación (MICINN)Unión Europea. FP7Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

The cradle of giants: insights into the origin of Scherotheca Bouché, 1972 (Lumbricidae, Crassiclitellata) with the descriptions of eight new species from Corsica, France

Copyright BOLD © 2014-2022International audienceScherotheca Bouché, 1972 is a highly diverse genus of Lumbricidae Rafinesque-Schmaltz, 1815, broadly distributed from Northern Italy and Corsica Island to the Pyrenees and Northeastern Iberian Peninsula. A recent survey of earthworm species diversity in Corsica resulted in the identification of 12 operational taxonomic units (OTU) within Scherotheca and the closely related genus Eumenescolex Qiu & Bouché, 1998, based on both morphological characters and COI barcodes. In this work, we complete molecular analyses to provide a dataset including four DNA markers (COI, 16S, 28S and ND1) and analyze it through Bayesian phylogeny reconstruction and barcode gap analysis. Our results highlight the existence of eight phylogenetically and morphologically distinct species, new for science, which we described herein as Scherotheca altarocca Marchán, Decäens & Domínguez, n. sp., Scherotheca marceli Marchán, Decäens & Domínguez, n. sp., Scherotheca darioi Marchán, Decäens & Domínguez, n. sp., Scherotheca boccaverghju Marchán, Decäens & Domínguez, n. sp., Scherotheca qiui Marchán, Decäens & Domínguez, n. sp., Scherotheca litoralis Marchán, Decäens & Domínguez, n. sp., Scherotheca capcorsana Marchán, Decäens & Domínguez, n. sp. and Scherotheca mausoleana Marchán, Decäens & Domínguez, n. sp. The diversity of the genus in Corsica has thus increased from four to 12 species. In addition, Eumenescolex emiliae Qiu & Bouché, 1998 appears phylogenetically nested within the Corsican Scherotheca, justifying amendment of the name to Scherotheca emiliae (Qiu & Bouché, 1998) n. comb. leading to 13 Corsican species in the genus. We further discuss diversity patterns, phylogenetic relationships and biogeographical history of the genus in the Corsica Island

The cradle of giants: insights into the origin of Scherotheca Bouché, 1972 (Lumbricidae, Crassiclitellata) with the descriptions of eight new species from Corsica, France

Copyright BOLD © 2014-2022International audienceScherotheca Bouché, 1972 is a highly diverse genus of Lumbricidae Rafinesque-Schmaltz, 1815, broadly distributed from Northern Italy and Corsica Island to the Pyrenees and Northeastern Iberian Peninsula. A recent survey of earthworm species diversity in Corsica resulted in the identification of 12 operational taxonomic units (OTU) within Scherotheca and the closely related genus Eumenescolex Qiu & Bouché, 1998, based on both morphological characters and COI barcodes. In this work, we complete molecular analyses to provide a dataset including four DNA markers (COI, 16S, 28S and ND1) and analyze it through Bayesian phylogeny reconstruction and barcode gap analysis. Our results highlight the existence of eight phylogenetically and morphologically distinct species, new for science, which we described herein as Scherotheca altarocca Marchán, Decäens & Domínguez, n. sp., Scherotheca marceli Marchán, Decäens & Domínguez, n. sp., Scherotheca darioi Marchán, Decäens & Domínguez, n. sp., Scherotheca boccaverghju Marchán, Decäens & Domínguez, n. sp., Scherotheca qiui Marchán, Decäens & Domínguez, n. sp., Scherotheca litoralis Marchán, Decäens & Domínguez, n. sp., Scherotheca capcorsana Marchán, Decäens & Domínguez, n. sp. and Scherotheca mausoleana Marchán, Decäens & Domínguez, n. sp. The diversity of the genus in Corsica has thus increased from four to 12 species. In addition, Eumenescolex emiliae Qiu & Bouché, 1998 appears phylogenetically nested within the Corsican Scherotheca, justifying amendment of the name to Scherotheca emiliae (Qiu & Bouché, 1998) n. comb. leading to 13 Corsican species in the genus. We further discuss diversity patterns, phylogenetic relationships and biogeographical history of the genus in the Corsica Island

Unearthing the historical biogeography of Mediterranean earthworms (Annelida:Hormogastridae)

Aim: The genetic diversity and distribution of earthworm species in the Mediterranean Basin has been influenced by their low vagility, as well as by the basin’s complex geological and climatic history. Within this context, our objective was to evaluate the evolutionary history of hormogastrid earthworms by exploring their phylogeny, reconstructing ancestral areas and identifying potential vicariance and dispersal events. Location: Western Mediterranean region, encompassing the geographical range of the family Hormogastridae (four genera, 30 species and subspecies). Methods: We sampled the easternmost area of the hormogastrid range and integrated 606 new sequences with all the molecular data available from previous studies on the westernmost area. Mitochondrial and nuclear markers were amplified and sequenced, and the hormogastrid phylogeny (using Bayesian and likelihood methods) and networks were investigated. Ancestral-area reconstructions were implemented in rasp. Results: Ancestral-area reconstructions provided similar results for alternative phylogenetic hypotheses, placing the origin of Hormogastridae between southern France and the north-eastern Iberian Peninsula, and highlighting north–central Sardinia as a key ancestral area for diversification of eastern Hormogastridae (Hormogaster redii and H. samnitica). Multiple vicariance and dispersal events were detected, indicating a complex evolutionary history. Sardinian populations of H. samnitica and H. redii were not monophyletic but were related to populations from other areas, suggesting that Sardinia is a more complex biogeographical region than anticipated. Our results identified a phylogenetic relationship between the southern Sardinian fauna and that of Sicily, as well as relationships between the fauna of north-eastern Sardinia and those of the Italian Peninsula and the Tuscan Archipelago. Main conclusions: Our results suggest a complex evolutionary history for hormogastrid earthworms, showing the possibility of many dispersal and vicariance events and multiple faunal interchanges between land-masses, which may reflect the biogeographical complexity of the Mediterranean Basin

Perspectives in Earthworm Molecular Phylogeny: Recent Advances in Lumbricoidea and Standing Questions

International audienceEarthworm systematics have been limited by the small number of taxonomically informative morphological characters and high levels of homoplasy in this group. However, molecular phylogenetic techniques have yielded significant improvements in earthworm taxonomy in the last 15 years. Several different approaches based on the use of different molecular markers, sequencing techniques, and compromises between specimen/taxon coverage and phylogenetic information have recently emerged (DNA barcoding, multigene phylogenetics, mitochondrial genome analysis, transcriptome analysis, targeted enrichment methods, and reduced representation techniques), providing solutions to different evolutionary questions regarding European earthworms. Molecular phylogenetics have led to significant advances being made in Lumbricidae systematics, such as the redefinition or discovery of new genera (Galiciandrilus, Compostelandrilus, Vindoboscolex, Castellodrilus), delimitation and revision of previously existing genera (Kritodrilus, Eophila, Zophoscolex, Bimastos), and changes to the status of subspecific taxa (such as the Allolobophorachaetophora complex). These approaches have enabled the identification of problems that can be resolved by molecular phylogenetics, including the revision of Aporrectodea, Allolobophora, Helodrilus, and Dendrobaena, as well as the examination of small taxa such as Perelia, Eumenescolex, and Iberoscolex. Similar advances have been made with the family Hormogastridae, in which integrative systematics have contributed to the description of several new species, including the delimitation of (formerly) cryptic species. At the family level, integrative systematics have provided a new genus system that better reflects the diversity and biogeography of these earthworms, and phylogenetic comparative methods provide insight into earthworm macroevolution. Despite these achievements, further research should be performed on the Tyrrhenian cryptic complexes, which are of special eco-evolutionary interest. These examples highlight the potential value of applying molecular phylogenetic techniques to other earthworm families, which are very diverse and occupy different terrestrial habitats across the world. The systematic implementation of such approaches should be encouraged among the different expert groups worldwide, with emphasis on collaboration and cooperation