Eridantes Crosby & Bishop, 1933

Prentice, Thomas R. & Redak, Richard A., 2013, A new species of the spider genus Eridantes Crosby & Bishop from the southwestern United States and mainland Mexico with a revised diagnosis of the genus (Araneae, Linyphiidae, Erigoninae), Zootaxa 3616 (4), pp. 357-366 : 358

Eridantes Crosby & Bishop, 1933

Type species. Lophocarenum erigonoides Emerton, 1882 by original designation.

Diagnosis. Eridantes is distinguished from those of all other similar linyphiid genera ( Crosbyarachne Charitnov , Dismodicus Simon , Baryphyma Simon , and Satilatlas Keyserling ) by the following two male characters: the mesal rather than ectal position of the paracymbium (narrowly underlying the proximomesal edge of the cymbium; Figs 5, 9 : P) and the broadly divided dorsal and ventral sclerites of the largely membranous radix ( Figs 5, 9 : R). We propose that the above character states are synapomorphies of Eridantes . Females are most likely to be confused with those of Pocadicnemus Simon ( P. pumilla (Blackwall) , P. americana Millidge, and P. occidentalis Millidge ) but can be readily distinguished by the flattened epigynum (ventrally protruding in Pocadicnemus), the medially positioned metatarsal trichobothrium (distally positioned in Pocadicnemus), and the absence of TmIV (present in Pocadicnemus).

Description. Length 1.5–1.9. Dorsal tibial spines 1-1-1-1, Tm IV absent, tarsal claws pectinate, both eye rows procurved (AER viewed from in front), cheliceral and abdominal stridulatory structures present ( Figs 10–13 ). Males: presence of PME cephalic lobe, prosomal pits, and lateral sulci ( Figs 1, 2 ); absence of spine on palpal patella; sternite and pleurites of pedicel juxtaposed; paracymbium narrowly underlying proximomesal edge of cymbium ( Figs 5, 9 : P) but dorsoectally articulated with base of cymbium (this portion of paracymbium not visible in unexpanded bulb); sperm duct with sudden constriction prior to entry into suprategulum, protegulum weakly developed, tailpiece flattened and bent near ventral edge of sclerotized portion of suprategulum ( Figs 5, 9 : TP), column membranous ( Figs 5, 9 : CL), both distal ( Fig 6 : DSA) and marginal suprategular apophyses ( Fig 9 : MSA) present (the latter very difficult to see in E. diodontos n. sp. but distinguishable in many males; presence undetermined in E. utibilis ), radical division largely membranous with sclerites broadly divided around membranous portion of radix ( Figs 5, 9 : R), embolic division ( Figs 5, 9 : ED) in the form of an apical attenuate semicircularly curved sclerotized structure winding from the thickened dorsomesal portion toward dorsoectal edge and back toward the ventromesal edge ( Figs 5, 9 : E), slender embolic tip (flattened and bifurcate in E. utibilis ) lying inside the distomesal edge of the tegulum, true embolic membrane (see Hormiga 1994) absent but sperm duct leaving radix and entering embolic division within a membranous sheath prior to entering the sclerotized portion of embolus, membrane ( Figs 5, 9 : M) articulated with sclerotized portion throughout length of embolus (membranous condition undetermined in E. utibilis ). Females: epigynum of E. erigonoides and E. diodontos n. sp., with mshaped internal carinae visible in ventral view (refer to Crosby & Bishop 1933: fig 158; Figs 14, 16 , respectively); epigynum of E. utibilis with an elongate, triangular structure, posteriorly broad and bluntly pointed anteriorly with spermathecae closely adjacent near posterior margin (refer to Paquin & Duperre 2006: fig 28).

Figures

FIGURES 5 – 9. Eridantes spp., males. 5 – 8, E. diodontos n. sp.: 5, palpus, mesoventral view, 6 palpus, ectal view, 7, palpus, mesal view, 8, palpal tibia, dorsal view, 9, E. erigonoides (Emerton), palpus, mesoventral view. Abbreviations: CL: column; DSA: distal suprategular apophysis; E: embolus; ED: embolic division; EJ: ejaculatory duct (constricted portion of duct); F: fundus; M: membrane; MSA: marginal suprategular apophysis; P: paracymbium; PT: protegulum; PTA: palpal tibial apophysis; R: radix; SD: sperm duct; SPT: suprategulum; ST: subtegulum; T: tegulum; TP: radical tailpiece.

FIGURES 10 – 16. Eridantes diodontos n. sp. 10 – 11, male: 10, cheliceral striae, 11, epigastric plate striae; 12 – 16, female: 12, cheliceral striae, 13, epigastric plate striae, 14, cleared epigynum, ventral view, automontage. 15, epigynum (SEM), ventral view, 16, epigynum, ventral view. Abbreviations: CD: copulatory duct; CO: copulatory opening; MP: median plate; FD: fertilization duct; IC: internal carinae; S: spermatheca; VP: ventral plate.

FIGURES 1 – 4. Eridantes diodontos n. sp. 1 – 2, male: 1, carapace, lateral view, 2, carapace, dorsal view; 3 – 4, female: 3, carapace, lateral view, 4, carapace, dorsal view.