Systematics of the genus Dilta Strand, 1911 (Machilidae) in the Canary Islands (NW Africa, Spain) with comments on the phylogeny of Microcoryphia (Insecta) Author Palacios-Martinez, Iñigo Author Jiménez-Ruiz, Yolanda Author Otero-Ferre, Pau Author García-París, Mario text Zoologischer Anzeiger 2025 2025-07-31 317 8 1 18 https://doi.org/10.1016/j.jcz.2025.05.005 journal article 10.1016/j.jcz.2025.05.005 1873-2674 16971179 3.2. Phylogenetic relationships od Dilta Strand, 1911 Phylogenetic analyses based on Bayesian analyses of the cox1 + 18S sequence data set using the newly sequenced specimens ( Table 1 ) show a topology poorly supported at the basal level ( Fig. 2 ), with, however, some well supported basal nodes. The family Meinertellidae , represented only by two species of Machilinus (BPPc = 1), is the sister group to the family Machilidae , with however a low support for the monophyly of Machilidae (BPPc = 0.58). The two species of Machilinus analyzed ( M. gredosi , and Machilinus sp. A cf. bejarensis ) are sister to each other (BPPc = 1; Fig. 2 ). There are three main clades within Machilidae disposed in a polytomy: 1) The Catamachilis lineage (BPPc = 1), with C. ancorata emerging as the sister species to the remaining members of the clade. Within this clade, C . amara was identified as the sister to C. franzi plus C. clipeata , with poor support (BPPc = 0.58), while C. franzi and C. clipeata showed a close relationship with high confidence (BPPc = 0.99). 2) Lepismachilis and Machilidae indet. appear as a well-supported clade (BPPc = 1), showing the uncertained samples as the closest relatives to Lepismachilis . Within this cluster, Lepismachilis ( Lepismachilis ) y-signata is sister to the subgenus Berlesilis , which included in our analyses L. (B.) targionii and L. (B.) affinis ; the relationship between them supported with a high confidence level (BPPc = 1). 3) A third, supported clade (BPPc = 0.94) split into two subclades: one consisting of the studied species of Dilta (BPPc = 0.94), and another where Machilis (M.) dragani appeared related with low confidence (BPPc = 0.60) to both P. hispanica (BPPc = 1) and the species of Praemachiloides (BPPc = 0.93), including P. tarsispina and P. janetscheki ( Fig. 2 ). Within the Dilta subclade, the Iberian Dilta (D.) sp. C plus the Balearic Dilta (D.) sp. E (BPPc = 0.98) are sister to the remaining Dilta , being Dilta (D.) sp. F plus Dilta (D.) similis (BPPc = 1) sister to the clades of Dilta (D.) fastuosa plus Dilta (D.) cf. saxicola (BPPc = 1) and the subgenus Budilta that included the Canarian taxa (BPPc = 1). Among the Canarian species, Dilta (B.) sp. D (= Dilta islabonita sp. nov. ), is sister to Dilta (B.) sp. A (= Dilta tilosina sp. nov. ), and Dilta (B.) sp. B (= Dilta benahoarense sp. nov. ) (BPPc = 0.96). Phylogenetic analyses of Dilta , using the ITS2 fragment, revealed a clear division into two distinct clades supported by high posterior probabilities (BPPits = 1) ( Fig. 3 ): 1) The clade formed by the species included in the subgenus Budilta , which included the specimens from La Palma: Dilta (B.) sp. D as the sister species to the other two (BPPits = 0.58): Dilta (B.) sp. B (BPPits = 0.88) and Dilta (B.) sp. A (BPPits = 1); 2) The Dilta s. str. clade, where the continental species of the study were included, with Dilta (D.) fastuosa sister to three subclades (BPPits = 0.97): Dilta (D.) cf. saxicola ; a clade comprising Dilta (D.) similis and Dilta (D.) sp. F (BPPits = 0.98); and a clade consisting of Dilta (D.) sp. E and Dilta (D.) sp. C (BPPits = 0.56; Fig. 3 ). Phylogenetic analyses of La Palma specimens within the subgenus Budilta , conducted using cox1 and incorporating GenBank sequences from other Canary Islands ( Table 1 ; Macías-Hern´andez et al., 2018) ( Fig. 4 ), revealed Dilta (Budilta) islabonita (also referred as Dilta sp. D ) from La Palma as the sister species to the other species (BPPbud = 1). The remaining sequences formed a polytomy with three subclades: 1) Dilta (B.) tilosina ( Dilta sp. A ) from La Palma (BPPbud = 1); 2) MH279718 from La Gomera; and 3) Dilta (B.) benahoarense ( Dilta sp. B ) from La Palma as the sister species to MH279717 from Tenerife (BPPbud = 1; Fig. 4 ). 3.3. Taxonomic results All specimens studied ascribed to the genus Dilta were characterized by presenting subrectangular-rounded ocelli in sublateral position ( Fig. 5A ), the coxal styli on 2nd and 3rd pair of legs ( Fig. 5D ); the 1 + 1 eversible vesicles on II-VII segments ( Fig. 5F ); ovipositor of tertiary type ( Fig. 5E ) as previously considered by Verhoeff (1910) , Mendes (1990) , and Sturm and Bach de Roca (1993) . To identify evolutionary units ( e.g., species) within Dilta , we used levels of congruence between nuclear, mitochondrial markers ( Fig. 4 ) and morphology ( Figs. 5–8 ). Clades were treated as independent taxa when all the specimens included in a mtDNA clade were also included in a distinct nuclear lineage and supported by clearly diagnosable morphological characters ( Figs. 5–7 ). We therefore adopted the evolutionary species concept ( Wiley, 1978 ; Wiley and Mayden, 2000 ), which considers that “ a species is a lineage of ancestral descendant populations which maintains its identity from other such lineages and which has its own evolutionary tendencies and historical fate ” . Using this scheme ( Fig. 3 ) (see discussion) we raised the diversity of Dilta from 21 to 24 species, and within the subgenus Budilta from one to four species. The new species, described in detail in the following species account paragraphs are named with reference to cultural or geographical aspects of the island of La Palma, where they live. Descriptions are made following the schemes of Kaplin ( e.g., Kaplin, 2019c ).