The velvet spiders: an atlas of the Eresidae (Arachnida, Araneae)

Abstract

The family Eresidae C. L. Koch, 1850 is reviewed at the genus level. The family comprises nine genera including one new genus. They are: Adonea Simon, 1873, Dorceus C. L. Koch, 1846, Dresserus Simon, 1876, Eresus Walckenaer, 1805, Gandanameno Lehtinen, 1967, Loureedia gen. n., ParadoneaLawrence, 1968, Seothyra Purcell, 1903, and Stegodyphus Simon, 1873. A key to all genera and major lineages is provided along with corresponding diagnoses, as well as descriptions of selected species. These are documented with collections of photographs, scanning electron micrographs, and illustrations. A new phylogeny of Eresidae based on molecular sequence data expands on a previously published analysis. A species of the genus Paradonea Lawrence, 1968 is sequenced and placed phylogenetically for the first time. New sequences from twenty Gandanameno Lehtinen, 1967 specimens were added to investigate species limits within the genus. The genus Loureedia gen. n. is proposed to accommodate Eresus annulipes Lucas, 1857. Two species, Eresus semicanus Simon, 1908 and Eresus jerbae El-Hennawy, 2005, are synonymized with Loureedia annulipes comb. n. One new species, Paradonea presleyi sp. n. is described. Eresus algericus El-Hennawy, 2004 is transferred to Adonea Simon, 1873. The female of Dorceus fastuosus C. L. Koch, 1846 is described for the first time. The first figures depicting Paradonea splendens (Lawrence, 1936) are presented.

First data on spiders (Arachnida: Araneae) from dry dipterocarp forests of Thailand

“…This species was known to be distributed in India and Myanmar (Kraus and Kraus 1988), but there had been only one reported finding from Tak province, northwestern Thailand (Ono 1995). Therefore, the locations of the present records in Huay Sai and the Sakaerat indicate the southernmost and easternmost distribution range of this genus (Miller et al 2012). Although the genus is known for its social manner of living (Johannesen et al 2007), the present specimens were collected solitarily in typical nests found in grass undergrowth and their social behavior was not observed.…”

Female genital morphology and sperm storage in the velvet spiderEresus kollari(Araneae: Eresidae)

“…As sperm was always absent in the anterior bulge and only present in the lobulated spermathecae, we conclude that the bulge is not involved in sperm storage. Thus, the term ''spermathecal head'' used by Miller et al (2012) is misleading as it implies some role in sperm storage. Whether the anterior bulge is somehow involved in the mating process cannot be answered based on our data.…”

“…Interestingly, this part is somewhat ambiguously defined. For example, Miller et al (2012) named it ''spermathecal head '' whereas Ř ezáč et al (2008) defined it as ''copulatory ducts''. Certainly, this different terminology also implies different functions as copulatory ducts are used for the transport of sperm into the spermatheca whereas the spermathecal head as part of the spermatheca is likely related to sperm storage.…”

“…Phylogenetically the most basal group of entelegynous spiders are velvet spiders (Eresidae) (summary in Miller et al 2012). They are a small spider family with 96 species.…”

South African National Survey of Arachnida (SANSA): review of current knowledge, constraints and future needs for documenting spider diversity (Arachnida: Araneae)

“…Eresids are a group of considerable arachnological interest, primarily because of the evolution of subsocial and quasisocial species from solitary ancestors in the genus Stegodyphus, behaviour that is absent in all of the other genera of the family (Kraus & Kraus, 1988;Miller et al, 2012). Not surprisingly, the rich eresid fauna of South Africa has led to considerable research being undertaken here, to the point that Stegodyphus are undoubtedly the best studied genus in the country with regards to their biology and diversity.…”