French Mediterranean islands as a refuge of relic earthworm species: Cataladrilus porquerollensis sp. nov. and Scherotheca portcrosana sp. nov. (Crassiclitellata, Lumbricidae)

Abstract

The area comprising the Pyrenees, Northeast Spain, Southern France and Corsica-Sardinia supports a large part of the diversity of Lumbricidae earthworms, including most species of the endemic genera Prosellodrilus, Cataladrilus and Scherotheca. In this region, the probability of encountering new species for science is significant, especially in scarcely sampled localities. In this study, we describe two unidentified species recently collected in the Hyères Archipelago (France), which we assigned to the genera Cataladrilus and Scherotheca based on morphological characters and molecular phylogenetic analyses. Other species of Scherotheca from Montpellier (including the type species of the genus, Sc. gigas gigas) were included in the analysis to clarify their conflicting systematics. A reduced molecular marker set (COI, 16S, 28S and ND1) proved as successful as larger marker sets for identifying phylogenetic relationships within the Lumbricidae. Remarkable disjunctions between both Cataladrilus porquerollensis Marchán & Decäens sp. nov., Scherotheca portcrosana Marchán & Decäens sp. nov. and their most closely related relatives, suggesting a strong influence of paleogeographic events on the earthworm fauna of the area and a possible role of near-shore islands as refugia for relict taxa. Genetic distances and branch lengths supported the elevation of some subspecies of Scherotheca to specific status as well as the retention of other subspecies, highlighting the importance of testing for such delimitation with molecular methods.

The disjunct distribution of relict earthworm genera clarifies the early historical biogeography of the Lumbricidae (Crassiclitellata, Annelida)

“…Sequences reported by Domínguez et al (2015), Domínguez et al (2018), Pérez‐Losada et al (2009), Pérez‐Losada et al (2011), Pérez‐Losada et al (2015), Paoletti et al (2016), de Sosa et al (2019), Bozorgi et al (2019), Jiménez et al (2021), and Marchán et al (2020, in press) including representatives of most of the Lumbricidae genera and two members of the closest families (Hormogastridae and Criodrilidae) were downloaded from GenBank and used as a reference dataset. The list of species and reference to the publication on which they were provided are shown in Appendix .…”

Catch-All No More: Integrative Systematic Revision of the Genus Allolobophora Eisen, 1874 (Crassiclitellata, Lumbricidae) with the Description of Two New Relict Earthworm Genera

“…Sequences were aligned using MAFFT v.7 [20] with default parameters and concatenated in BioEdit [21], obtaining a sequence of 3,260 base pairs for each species. Sequences reported by Dominguez et al [2], Domínguez et al [17], Pérez-Losada et al [18], Pérez-Losada et al [22], Pérez-Losada et al [23], Paoletti et al [12], de Sosa et al [11], Bozorgi et al [24], Jiménez Pinadero et al [25], and Marchán et al [26] with representatives of most Lumbricidae genera and two members of the closest families (Hormogastridae and Criodrilidae) were downloaded from GenBank and used as a reference dataset. The included species and their source publications are listed in Supplementary Table 1.…”

“…Phylum Annelida Lamarck, 1802 Subphylum Clitellata Michaelsen, 1919 Allolobophora is clearly separated from Gatesona by the absence of pigmentary dots in cephalic segments, by its general pigmentation (if present: green vs. brown), by the absence of very conspicuous genital papillae between segment 9 and the end of the clitellum and by the start of the clitellum (28-73 vs. [23][24][25][26][27]. They also differ in the position of the spermathecae (variable in 7/8, 8/9, 9/10, and 10/11 vs. 9/10, 10/11, and (11/12)).…”

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

“…Eumenescolex (Qiu and Bouché 1998) is a poorly known genus of Western Mediterranean earthworms, with a strongly disjunct distribution (France, Italy, Spain), which is otherwise consistent with the geological history of the region. Members of the genus have been suggested to be related to Scherotheca [60], but they differ strikingly in body size and lifestyle from most species, other than the Corsican endemics. Molecular phylogenetics data on these elusive earthworms could provide more information on the intriguing role of Corsica, Sardinia, and Southern France in the evolution of lumbricids before they drifted apart in the Oligocene [61].…”

“…Molecular phylogenetics data on these elusive earthworms could provide more information on the intriguing role of Corsica, Sardinia, and Southern France in the evolution of lumbricids before they drifted apart in the Oligocene [61]. Scherotheca itself is a diverse genus, for which relatively little molecular phylogenetics data is available (but see [60] for four additional representatives, including a newly described one). In this case, molecular phylogenetics would serve as a starting point for determining their ancestral range (Spain, mainland France, or Corsica) and morphological radiation towards a giant anecic phenotype.…”