Lepthyphantinae, Simon, 1929

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 : 55-56

Lepthyphantinae new circumscription and Fickert’s gland homology ( Figs 7 , 12 )

Lepthyphantinae new circumscription is a very speciose lineage with more than 400 species (WSC 2025), concentrating about 70% of the diversity of the polyphyletic micronetines (sensu Saaristo & Tanasevitch 1996).

Saaristo’s (1975) Lepthyphantinae [partim] and Millidge’s (1977) Lepthyphantes group were later referred to as Micronetinae (Saaristo & Tanasevitch 1996), based on the presence of the Fickert’s gland in the male palp. In our analysis, the Lepthyphantinae (new circumscription) is supported by ten synapomorphies. The presence of a special seta on the patella of the male palp (char 126) is recovered as non-homoplasious, while the remaining changes, such as the presence of an ecto-basal cymbial process (char 33), a paracymbium of about the same size as the rest of the cymbium (char 46), paracymbium with an apophysis or process as a distal branch of its apical part (char 52), a sperm duct switchback (char 71), and an epigynum with a ventral plate scape (char 136) optimized as homoplastic.

The Fickert’s gland (char 103) was not recovered as a synapomorphy for any of the “micronetinae” clades, similar to the results of Arnedo et al. (2009). Our ancestral reconstruction ( Fig. 14A ) analysis suggests at least two independent origins of Fickert’s gland: one in the Lepthyphantinae , found in Lepthyphantes Menge Tenuiphantes Saaristo & Tanasevich Bolyphantes Koch , and Drapetisca Menge with a loss in Floronia Simon and a second origin within the Agyneta clade ( A. rurestris + A. ramosa Jackson ). The position of Floronia (together with Tapinopa Westring ) as sister group to the remaining Lepthyphante s group receives full support across all our analyses. Both Floronia and Tapinopa lack Fickert’s gland, and for this reason, Millidge (1977) placed them in the Oreonetides group.

Based on Merret’s (1963) illustrations, Saaristo & Tanasevitch (1996) noticed that the position of Fickert’s gland in Agyneta was different from that in the rest of Lepthyphantinae (sensu Saaristo, 1999), appearing in the former as a “small secondary dilatation within the embolus [proper]” instead of a larger one within the radix in the latter ( Figs 14B, C ). While we made no distinction between the two morphologies of the Fickert’s gland when coding them in our matrices, our results suggest that those structures might have separate origins and, thus, not be homologous. A detailed study of the structure of Fickert’s gland in both groups is needed to understand the evolution of this structure better.

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 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.

FIGURE 14. Fickert’s gland evolution hypothesis A, Ancestral state reconstruction (parsimony, unordered) of character 103 over the pruned preferred hypothesis tree. B and C Schematic illustration of the two different morphologies recognized for Fickert’s gland in Linyphiidae: B. Megalepthyphantes nebulosus (Sundevall), embolic division (ventrolateral view). C: Agyneta subtilis (O. Pickard-Cambridge), embolic divison (ventrolateral view). Blue color indicates the sperm duct with Fickert’s gland (fg) within the embolus (e) area. B and C modified after Merret (1963).