Systematic revision of the Savignia genus group (Araneae: Linyphiidae: Erigoninae) with notes on their cephalic lobe evolution

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  Systematic revision of the Savignia genus group (Araneae: Linyphiidae: Erigoninae) with notes on their cephalic lobe evolution Abstract The Savignia genus group includes nine morphologically complex yet similar genera where species were assigned based mainly on the cephalic lobes. Among these genera, males of Diplocephalus Bertkau, 1883, Savignia Blackwall, 1833 and Araeoncus Simon, 1884 show some of the most extraordinary cephalic lobes among dwarf spiders (Linyphiidae, Erigoninae). In this study we undertake the first phylogenetic analysis of the Savignia genus group. We use 269 morphological characters (175 newly defined) and 70 taxa (59 ingroup taxa) to reconstruct the relationships and evolutionary trends of cephalic lobes in this lineage. Our findings show that cephalic lobes with varying shapes and sizes appear in several Savignia genus group lineages, highlighting that it is not a good diagnostic character. The high support in several clades allows the redefinition of t...

The validity of Ancylometes birabeni (Carcavallo & Martínez, 1961) (Araneae: Ancylometidae)

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The validity of Ancylometes birabeni (Carcavallo & Martínez, 1961) (Araneae: Ancylometidae)

Abstract
Carcavallo & Martínez (1960; 1961) described four new species and proposed a new genus of Ctenidae Keyserling, 1877 from Argentina. Of these, Corinoctenus anomalosto mus Carcavallo & Martínez, 1961 and Corinoctenus green wayi Carcavallo & Martínez, 1960 were synonymized first with Ancylometes bogotensis (Keyserling, 1877) by Scia pelli & Gerschman (1970) and later removed and placed as junior synonyms of Ancylometes concolor (Perty, 1833) by Höfer & Brescovit (2000). The three remaining valid names are the genus Montescueia Carcavallo & Martínez, 1961 and its type species Montescueia leitaoi Carcavallo & Martínez, 1961, described based on a male from Salta prov ince in north-west Argentina, and Ancylometes birabeni Carcavallo & Martínez, 1961 described based on a female from Corrientes, north-east Argentina. Until recently, Ancy lometes was contained in the family Ctenidae Keyserling, 1877 but was transferred to the new family Ancylometidae Hazzi, Wood & Hormiga, 2025 by those authors. The trans fer of Ancylometes s.s. was well supported. In this work, we discuss the identity of A. birabeni, which possesses a cribellum and calamistrum and is unequivocally a ctenid of the subfamily Acanthocteninae.

Acknowledgement: I’d like to sincerely thank Danniella Sherwood for kindly sharing this manuscript with me through ResearchGate.

Sherwood, Danniella & Piacentini, Luis. (2025). The validity of Ancylometes birabeni (Carcavallo & Martínez, 1961) (Araneae: Ancylometidae). Arachnology. 20. 279-280.