Clavella, Oken, 1815

Consideration of Clavella View in CoL - Branch phylogeny

When Kabata (1979) proposed his phylogenetic tree of Lernaeopodidae based on morphology, he established its main branches: Salmincola branch, Charopinus Branch, Brachiella Branch, Lernaepoda branch, and Clavella Branch.

For Clavella View in CoL branch, he defined several sub-branches. The first sub-branch (A) included Clavellisa Wilson, C. B. 1915 View in CoL , Euclavellisa Heegaard, 1940 View in CoL , Clavellopsis Wilson, C. B. 1915 View in CoL , and Clavellodes Wilson, C.B. 1915 View in CoL . On the opposite side, sub-branch (B) comprised Clavella Oken, 1815 View in CoL —a diverse genus—along with sub-branch (C), which included Anaclavella Heegaard, 1940 View in CoL and Clavellominus Kabata, 1969. More distally, sub-branch (D) emerged, containing Proclavellodes Kabata, 1967 View in CoL , Alella, Leigh-Sharpe, 1925 View in CoL , and Kabatazu s Özdikmen, 2008 (formerly Advena View in CoL ; Kabata 1979). Kabata also positioned Clavellistes View in CoL within sub-branch (B) alongside Clavella View in CoL . At that time, Clavella branch View in CoL consisted of 11 Genera. Since then, several new genera have been described within this branch, including Nudiclavella Ho, 1975 View in CoL (whose status remains uncertain according to Kabata 1979), Mixtio Kabata, 1990 View in CoL , Pseudomixtio Kabata, 1990 View in CoL , and Clavellotis Castro & Baeza 1984 View in CoL (following the transfer of some species from Clavellopsis View in CoL to Clavellotis View in CoL by Kabata 1990). More recently, Maxiclavella View in CoL and Praeclavella View in CoL , were separated from C lavella ( Castro et al., 2022). Further taxonomic revisions are likely as suggested in the present study, particularly regarding species such as C. stellata View in CoL , whose classification requires verification, along with the true placement of Kabatazus View in CoL (= Advena View in CoL ) within the Clavella branch. View in CoL

A partial molecular analysis using representatives of this branch, based primarily on COI and 28s genes, provides insight into their phylogenetic relationships. Although COI is not strictly used for phylogenetic reconstruction, it has been employed in similar cases ( Sebone and Dippenaar 2024), and in other arthropods, such as Orthopteran (Lü et al., 2012) to infer evolutionary relationships. In this study, molecular data support Clavellisa View in CoL as a basal taxon relative to Clavella View in CoL , which is also consistent with morphological traits. Clavellisa View in CoL retains a biramous second antenna and a mandible with secondary dentition, whereas Clavella View in CoL exhibits a uniramous antenna (or at least a highly reduced exopod) and a mandible with primary dentition, though some species may bear a single secondary tooth). This confirms the evolutionary placement of Clavellisa View in CoL and its relationship with other genera analyzed at the time. However, the phylogenetic positions of other genera in sub-branch (A) alongside Clavellisa View in CoL may require reassessment due to notable morphological differences, particularly in body structure (e.g. cephalothorax versus trunk orientation) and mandibular dentition.

The present study also supports a clade containing Clavellotis and Alella , though the latter's placement may not align with Kabata’s (1979) classification, given differences in maxilla development and primary dentition. Additionally, the results suggest a close relationship between Clavella and Maxiclavella ( Castro et al., 2022) , while Praeclavella ( Castro et al., 2022) appears to have diverged before the diversification of Clavella .

Overall, these findings indicate that new phylogenetic relationships may emerge among the genera currently assigned to the Clavella branch , leading to potential taxonomic reassignments and descriptions of new genera (e.g., Castro et al., in litteris).