Ipainae

Silva-Moreira, Thiago Da, Kulkarni, Siddharth & Hormiga, Gustavo, 2025, A total evidence phylogenetic analysis of the spider family Linyphiidae (Araneae, Araneoidea), Zootaxa 5685 (1), pp. 1-78 : 57

Ipainae

Saaristo (2007) erected the subfamily Ipainae to group the genera Ipa Saaristo Epibellowia Tanasevitch , Metaleptyphantes Locket, Solenysa Simon , Uralophantes Esyunin , Wubanoides Eskov , and Epigytholus Tanasevitch. Saaristo (2007) enumerated a long list of diagnostic features for the subfamily, including the radical lamella, “the shape of the paracymbium” [sic], a filiform embolus, and a movable epigynum “whereas the first and last are possible autapomorphies of the entire family” ( Saaristo 2007:38). In the same study, the author also hypothesized that Ipainae would be the sister group to Micronetinae as they share the presence of Fickert’s gland in the male palp ( Saaristo 2007). However, as pointed by Arnedo et al. (2009), none of those assertions were tested as characters in phylogenetic analysis, and thus, the monophyly of Ipainae was regarded by them with some skepticism. The phenotypic analysis of Tu & Hormiga (2011) placed Solenysa within the “Distal erigonines” clade. A subsequent study, based entirely on molecular data ( Wang et al. 2015), included for the first time more than one ipaine genus ( Solenysa and Wubanoides ) and did not support the monophyly of Ipainae . Silva-Moreira & Hormiga (2022) coded Ipa keyserlingi (Ausserer) together with some of the species of Solenysa used in Tu & Hormiga (2011) and tested the monophyly of Ipainae for the first time in a cladistic framework, with results similar to those of Wang et al. (2015), rejecting again Ipainae monophyly but this time with a phenotypic dataset.

We have tested the monophyly of Ipainae in a total evidence framework. We could not obtain Ipa specimens suitable for sequencing, so our hypothesis of placement for this genus is based on phenotypic data. Our hypothesis is congruent with those of Wang et al. (2015) and Silva-Moreira & Hormiga (2022). None of our analyses recovered Ipainae as a clade (see Table 5). Ipa position varied widely depending on the dataset and optimality criteria (always with very poor nodal support—see Supplementary files) but never as sister to Solenysa or Wubanoides , being the latter consistently recovered as sister to Parawubanoides within the Lepthyphantinae ( Fig. 7 ).

Finally, the position of Solenysa was strongly influenced by the inclusion of molecular data. The MORPH dataset places Solenysa in Erigoninae , sister to Gonatium rubens ( Fig. 12 ), while both DNA and TE datasets place Solenysa genus in Clade B, sister to a clade comprising Allomengea + Agyneta clade + Microneta clade + Erigoninae ( Fig. 8 ) a result similar to those of Wang et al. (2015). In both cases, Solenysa is strongly supported as a natural group. The genus is supported by five non-homoplasious synapomorphies: lamella characteristica posterior apophysis flattened (char 120), epigynum attached to opisthosoma trough a solenoid (char 128), clypeus with pits (char 172), prosomal pits (char 198) and prosomal petiole (char 199).

While the placement of the different genera of Ipainae is not fully resolved, the data strongly suggest that this subfamily is not a natural group. The distinctive features pointed out by Saaristo (2007) are very likely convergent features, as suggested by our MORPH dataset. The Ipainae subfamily should not be used as a taxonomic rank as it refers to a non-natural group.

Figures

FIGURE 7. Partial tree from the preferred hypothesis for linyphioids (M4_MB). Clade B (part). Turinyphia clairi, Centromerus clade, and Lepthyphantinae. Black arrow points to Wubanoides placement, Black-colored squares represent nodes with posterior probability =1; gray-colored squares represent nodes with posterior probability between 0.95 and 0.99.

FIGURE 8. Partial tree from the preferred hypothesis for linyphioids (M4_MB). Clade B (part). Solenysa genus, Allomengea sp., Agyneta clade, and Microneta clade. Black-colored squares represent nodes with posterior probability =1; gray-colored squares represent nodes with posterior probability between 0.95 and 0.99.

FIGURE 12. Optimization of the phenotypic matrix characters (DELTRAN optimization) on the pruned preferred hypothesis tree. Orange box indicates Clade A circumscription. Red box indicates Clade B circumscription. Black circles indicate nonhomoplasious optimizations (synapomorphies/ autapomorphies), while white circles indicate homoplasious transformations.