Eresidae C. L. Koch

Miller, Jeremy A., Griswold, Charles E., Scharff, Nikolaj, Řezac, Milan, Szűts, Tamas & Marhabaie, Mohammad, 2012, The velvet spiders: an atlas of the Eresidae (Arachnida, Araneae), ZooKeys 195, pp. 1-144 : 12-18

Eresidae C. L. Koch

Chercheuses ( Erraticae ) Walckenaer, 1802: 248; Walckenaer 1805: 21.

Eresidae C. L. Koch, 1850: 70; Simon 1892: 248-254; Lehtinen 1967: 385-390; Griswold et al. 2005: 24-27.

Nomenclatural note.

Walckenaer (1802) divided spiders into 18 “Famillies.” At this time, concepts of nomenclature were distinctly different from our modern understanding. All spider species were referred to by a binomen with “Aranea” as the genus regardless of “famillie” placement. Chercheuses (Erraticae) contained one species: Aranea cinnaberina (now Eresus kollari ). Because Walckenaer’s family name was not formed from the stem name of the type genus, it was not considered valid once international codes of nomenclature were adopted starting in 1905 ( International Commission on Zoological Nomenclature 1905). For an enlightening discussion of Walckenaer’s and related systems of spider classification, see Edwards (2011).

Diagnosis.

Distinguished from other three-clawed, eight-eyed, cribellate entelegyne spiders except Penestomidae by their subrectangular carapace and clypeal hood; distinguished from Penestomidae by the absence of an RTA on the male palpal tibia, the absence of a median apophysis arising from the palpal tegulum, the absence of a posterior lobe of the epigynum (the posterior lobe is a separate plate in Penestomidae ; compare Figs 45A, 93A with Miller et al. 2010b: fig. 8A), and the absence of a tapetum in the indirect eyes. The eye arrangement in Eresidae is distinctive, with a straight anterior eye row and strongly recurved posterior eye row, with the median eyes close together, the ALE near the anterior lateral corners of the carapace, and the PLE position on the carapace at least 0.2 (Figs 8B, D, F, H, J, L, 9B, D, F, H, J, L, 10 B, D, F, H, J, L, 11B, D, F, H, J, L); by contrast, Penestomidae have the anterior eyes subequally spaced with the ALE placed about midway between the center and the corners of the carapace ( Miller et al. 2010b: fig. 1C), and the PLE position on the carapace ca. 0.1.

Description.

Somatic morphology:Carapace subrectangular in dorsal view; cephalic region may be strongly raised. Eight eyes in two rows, posterior eye row strongly recurved so that the PLE are set far back from the others (Figs 8B, D, F, H, J, L, 9B, D, F, H, J, L, 10 B, D, F, H, J, L, 11B, D, F, H, J, L). Tapetum absent from eyes. The anterior-median part of carapace extended ventrally into a clypeal hood (Figs 8A, C, E, G, I, K, 9A, C, E, G, I, K, 10A, C, E, G, I, K, 11A, C, E, G, I, K). Two or more setal morphologies typically present appearing as dark and white setae in museum specimens (Figs 35B, 81D, 91B). Chelicerae robust, may be contiguous (Fig. 19G) or excavated mesally (Fig. 68F), distal anterior part with dense cluster of strong setae near fang (Fig. 28C), usually with boss (Figs 28B, 46B, 56E, but see 56C); large single keel anterior to fang, may be serrate, with series of small denticles leading towards base of fang; there is no distinct fang furrow (Figs 34F, 91F). Female palp with tarsal claw (Fig. 92F). Legs usually short with two rows of trichobothria on tibiae and one distal trichobothrium on metatarsi. Bothria have series of transverse grooves proximally (Figs 25D, 38B, 45E, 92B). Tarsal organ small, capsulate, and positioned near the distal tip (Figs 38A, 46D, 92A). Major and median claws with series of teeth (Figs 38C, 92C). Linear calamistrum occupies entire length of metatarsus IV (Figs 25E, 38D, 46E, 92D), with a dorsal patch of smaller calamistral setae (i.e., with lines of teeth, Figs 25F, 31F, 38E, 46F, 67F, 82F, 92E). In some eresids, the line of primary calamistrum setae is not clearly distinguishable from the dorsal patch (Figs 25F, 31F, 46F, 67F). Abdomen generally oblong with distinct dorsal sigilla (Figs 3I, 4H, 19A, 47I, 89E). Posterior respiratory system comprises four simple tracheal tubes ( Lamy 1902; CEG, pers. obs. Stegodyphus and Dresserus ).

Male palp: Male palpal tibia without apophysis, with two rows of trichobothria (Figs 27F, 34E, 55F). Palpal bulb with sclerotized conductor that interacts with spiral embolus (Figs 27C, 34D, 41F, 90D), expansion occurs in both the basal and median haematodochae (Figs 12F, 13C, F, 15C, L). Axis of spiral typically proximal-distal with embolus encircling distal part (Figs 12B, 13B, H, J, 14I, 15B, H, K), occasionally more or less ventral-dorsal with embolus encircling ventral part ( Dresserus and Gandanameno ; Figs 12G, 13D, 33 I–K, 48 A–F).

Female genitalia: Epigynum present with entelegyne configuration, one pair of spermathecae (typically in a posterior position except in Dresserus and Gandanameno , where they are anterior), and spermathecal heads (typically in an anterior position and far from the spermathecae except in Dresserus and Gandanameno , where they are adjacent to the spermathecae; Figs 16 D–F, J–L, 17 D–F, 18 D–F, J–L, 22B, 29D, 37E, 42D, 45B, 59C, 65B, 76B, 82B, 86B, 93B); posterior lobe absent (compare Figs 45A, 93A with Miller et al. 2010b: fig. 8A).

Spinneret spigot morphology: ALS typically with multiple MAP (absent in Seothyra , Figs 77B, 78B) and a field of PI (Figs 36B, 94B). PMS with one to several mAP and a field of AC, occasionally elongated and divided into two lobes (female Dresserus and Gandanameno , Figs 36C, 57A, C), CY present (Figs 36 C–D, 57C, 58E) or uncertain. PLS with field of AC, MS positioned on dorsal part adjacent to ALS far from rest of field, may be accompanied by one ( Dorceus , Figs 30F, 32F) or two ( Eresus sandaliatus group, Loureedia gen. n., Seothyra , Stegodyphus , Figs 67D, 87 D, 95E) flanking AC (no MS-flanking AC in at least Dresserus and Gandanameno , Figs 36E, 57D, 58C, 61 B–C). Cribellum present with median division in most genera (Figs 57E, 77E, 87A, 94A, E), each half subdivided in Dresserus (Fig. 36F). Multiple epiandrous gland spigots present in male (Figs 22 E–F, 28D, 39F, 45F, 61 E–F, 65F, 74 E–F, 80 E–F, 85 E–F, 93F).

Phylogeny.

Our phylogenetic analysis is a modest expansion of Miller et al. (2010a) and the topology is congruent with the earlier study. The additions to the new analysis are two specimens of Paradonea variegata and twenty more specimens of Gandanameno . As reported previously, Eresidae is divided into two major clades: one consisting of Seothyra , Dresserus , and Gandanameno , the other containing the remaining genera including Paradonea (Figs 51, S1). In our topology, Paradonea sits on a long branch sister to a clade consisting of Eresus , Adonea , Loureedia gen. n., and Dorceus ; Stegodyphus is sister to this five-genus clade. Note that our exemplar for Paradonea is not the type species and the monophyly of this genus is uncertain. Our focus on sequencing Gandanameno was designed to elucidate species limits within the genus, in combination with morphological data (Figs 50, S2, S3). These results are discussed further in the section on Gandanameno , below.

Key to genera of Eresidae

(note: females of Paradonea striatipes Lawrence, 1968, Paradonea splendens (Lawrence, 1936), Paradonea parva (Tucker, 1920), and Paradonea presleyi sp. n. are unknown)