Bioacoustics of Eridantes diodontos

Description. Holotype male: total length 1.7. Carapace : length 0.78, width 0.61, cephalic width/carapace width 0.7, cephalic lobe present, carrying the PME ( Figs 1, 2 ), PME 1.0 diameters (long diameter) from the anterior margin of lobe, lobe width 0.28, widest at anterior ectal margin, lobe width/cephalic width 0.6,yellowishorange, more yellowish toward posterior, darker in the cephalic region, infuscated between posterior mid-line seta and base of cephalic lobe, margin with dark gray or black encircling band; in dorsal outline ( Fig 2 ) a slight constriction at the cephalic groove, from groove anterior margin evenly curved; anterior margin of cephalic lobe broadly angulate (rounded in E. erigonoides ), anterior corners more or less in line with posterior margin of ALE, PLE barely visible; lateral margins of lobe (dorsal sulci) parallel, dorsal setae on lobe procurved, anterior setae (from mid-line) curved ectally downward, margin with black encircling band, reduced in width anterior to level of coxa of palp; carapace in lateral view ( Fig 1 ) rising from posterior in nearly straight line to the level of the long posterior seta (anterior end of dorsal groove), then slightly and narrowly flattened to base of lobe, continuing in straight rise and then gently curving from level of posterior end of cavity toward highest point just posterior of PME, cephalic height 0.39, gently curving downward, most anterior point slightly overhanging concave portion which continues to AME (AME visible from above), one long dorsal mid-line setae, anterior socket with seta missing (in males with both setae present, anterior is also long but slightly shorter than posterior), length of posterior 0.16; cephalic lobe with small prosomal pit slightly above and behind PLE (more or less in line with PE group), pit at anterior end of relatively large cavity, surface smooth and shiny and bounded by lateral sulci, cavity widest near mid-length; clypeus slightly convex, single clypeal seta midway between AME and ventral margin of clypeus, clypeal height 0.15; clypeus, lower edge of pars cephalica, and pars thoracica with fine squamate microsculpture. Chelicerae : relatively stout, similar to color of anterior thoracic region, with clearly visible stridulatory striae, striae overlapping and auxiliary striae present ( Fig 10 ); inner anterior surface with three small setulose tubercles, one additional between the distal two on anteromesal face near cheliceral teeth; anterior margin with five teeth, second proximal largest, posterior margin with four large denticles. Eyes : PME 0.05; ALE largest 1.2X PME diameter, PLE only slightly larger than AME, AME smallest 0.04, separated from each other by approximately the radius of one and from the ALE by approximately one diameter; both eye rows procurved (AER viewed from in front); AME and LE groups and each PME encircled in black. Sternum and pedicel : both width and length of sternum 0.48, posterior extension between coxae IV broad, width slightly less than coxal width; setae relatively long and oriented toward mid-line, 0.4–0.5X length of posterior dorsal mid-line seta; color yellowish orange, similar to that of cephalic region, margin narrowly infuscated; sternite and pleurites of pedicel juxtaposed. Abdomen : color black without pattern, seta on dorsal and ventral surfaces reclined and relatively dense, epigastric plates over booklungs yellowish, similar in color to posterior portion of carapace; stridulatory striae not visible at 125X but SEM images reveal squamate striae ( Fig 11 ); spinnerets whitish. Legs : leg formula IV-I-II-III, dorsal tibial spines 1-1-1-1, respectively, TmI 0.46, TmIV absent, TiI l/d 5.3; leg I length/carapace length 2.45; tarsal claws pectinate (visible at 200X), superior claws of tarsi I & II with tines throughout length of claws, decreasing in length toward claw base, tines on tarsal claws III & IV fewer in number, only on basal portion of claws. Pedipalp : length femur/length femur I 0.66; tibia widest medially, tibial apophysis widest near half-length, with two teeth, darkened dorsal tooth bluntly pointed on mesal side, squared off on ectal side, the longer black ventral tooth extending in a tapering fashion from level of squared off ectal edge of dorsal tooth toward ectal edge of the tibia and with the more ectally angled distal end tapering abruptly to a point ( Figs 6–8 ); tibial trichbothria: one prolateral, one retrolateral ( Fig 8 ). Bulb : cymbium small only slightly longer than patella, cymbium length/femur length 0.56; paracymbium fully visible only in ventral view (similar in shape to that of E. erigonoides ; see Kaston 1948; fig 571), narrowly underlying proximoventral margin of mesal side of cymbium ( Fig 5 : P); tegulum ventrally protuberant ( Figs 6, 7 : T), in mesal and mesoventral views distal margin on mesal side of protegulum appearing carinate ( Fig 5, 7 ); protegulum small, not well developed ( Fig 6 : PT); terminus of tailpiece ( Fig 5 :TP) angularly rounded at sclerotized margin of suprategulum near cymbial margin, angled at dorsal transition to narrowed visible part, narrowed sclerite split into ventral and dorsal components between which lies membranous region of the radix ( Fig 5 : R) into which sperm duct passes through membranous column ( Fig 5 : SD, CL), dorsal and ventral sclerites merge into single sclerite distal to entry point of sperm duct, single sclerite continuing toward ectal side of bulb as a wide flattened embolic division ( Fig 5 : ED; with a membranous component) which tapers as it coils back to mesal side of bulb where slender tip ( Fig 5 : E) is supported by tegulum just inside of carinate apical margin on mesal side of bulb, sperm duct carried by membranous constituent ( Figs 5–7 : M) to ectoventral point of embolic curve where duct enters sclerotized portion; suprategulum sclerotized dorsally ( Fig 5 : SPT), terminal portion of DSA supports coiled embolus on ectal to ectoventral portions of embolus ( Fig 6 : DSA). Legs ( 3 ) I II III IV Palp Femur 0.59 0.51 0.43 0.59 0.39 Patella 0.19 0.18 0.16 0.20 0.18 Tibia 0.46 0.38 0.32 0.52 0.17 Metatarsus 0.35 0.33 0.30 0.40 – Tarsus 0.32 0.31 0.28 0.31 0.22 Total 1.91 1.71 1.49 2.02 0.96 Description. Allotype female : total length 1.9. Carapace : length 0.81, width 0.65, cephalic width/carapace width 0.75; coloration dark yellowish-orange in cephalic region, clypeus and area between eye rows lightly infuscated, more yellowish posteriorly; in lateral view ( Fig 3 ) rising steeply from base to approximately the level of posterior face of coxa II, then more-or-less rising in even arc, to highest point just posteriad of PME, height 0.34, then dropping in even arc to AME; clypeus relatively straight, sloping anteriorly to most anterior point at ventral margin of clypeus, height 0.12, single clypeal seta at about 0.55X distance between ventral margin of clypeus and AME; three long setae between dorsal groove and PME, from posterior to anterior decreasing in length, posterior seta 0.16; clypeus, ventral margin of pars cephalica, and pars thoracica with squamate microsculpture; in dorsal view ( Fig 4 ) with slight constriction (gently concave) near cephalic groove, cephalic region evenly rounded in front, width greatest at about level of anterior face of coxa II. Chelicerae : coloration as in pars cephalica, moderately stout with clearly visible stridulatory striae, striae overlapping ( Fig 12 ), medial striae (central striae between anterior and posterior cheliceral margins) more interrupted than in male, auxiliary striae present ( Fig 12 ), margins of fang furrows equipped with five teeth on anterior margin and four relatively large denticles on posterior margin, two small setose tubercles on inner face of anterior surface, 1 additional tubercle on dorsomesal face close to proximal tooth on the anterior margin. Eyes : PME 0.05, separated from each other by 0.9X the diameter, ALE subequal to PME, AME smallest, separated by 0.50–0.6X the diameter of one, PLE slightly smaller than ALE, PME–PLE 1.3X PME diameter, PME–AME 1.5X PME diameter, AME–ALE 1.5X AME diameter, both eye rows procurved (AER viewed from in front), PE and AME groups, and each PME encircled in black. Sternum and pedicel : coloration yellowish orange as in cephalic region, length and width 0.50, margin and extension between coxae IV infuscated; sternite and pleurites of pedicel separated by membrane (juxtaposed in male). Abdomen : setation, coloration of abdomen, spinnerets, and booklung plates ( Fig 13 ) as in holotype . Legs : leg formula IV-I-II- III, dorsal tibial spines 1-1-1-1, respectively, TmI 0.49, TmIV absent, TiI l/d 4.9, leg I length/ carapace length 2.41; pectination of tarsal claws as in male holotype . Pedipalp : tibial trichobothria, two retrolateral, one prolateral. Epigynum : width 0.23, length 0.17; median plate forming an inverted (seemingly) T-shaped structure ( Figs 14, 16 :MP; true shape ( Fig 15 : MP; furrow defining division between median and ventral plates not visible at 125X magnification); copulatory openings at junction of median and ventral plates at anterior termini of transverse component of median plate ( Figs 14–16 : CO, MP, VP, respectively); longitudinal component of median plate with sides appearing roughly parallel ( Figs 14, 16 : MP); darkened lateral carinae ( Fig 14 : IC) of median plate (stemming from anterior end of longitudinal component) loop laterally and extend posteriorly, together with carinae of the longitudinal component of median plate forming an m-shaped pattern ( Figs 14–16 ); spermathecae kidney-beanshaped ( Figs 14, 16 : S) with dorsolateral orientation, posterolaterally positioned, just anterior of and lateral to termini of transverse arm of median plate. Legs ( ♀ ) I II III IV Femur 0.59 0.54 0.46 0.63 Patella 0.21 0.20 0.19 0.20 Tibia 0.45 0.39 0.33 0.54 Metatarsus 0.36 0.33 0.32 0.40 Tarsus 0.33 0.32 0.28 0.32 Total 1.94 1.78 1.58 2.09 Variation. Males (n=7). Total length 1.55–1.7. Carapace : length 0.69–0.78, width 0.55–0.61, cephalic height 0.34–0.39; clypeal height 0.13–0.15, coloration varying from dark yellowish orange to yellow, but darker in cephalic region becoming more pale toward base of cephalothorax, area between eyes and clypeus often with light infuscation, one or both of long mid-line dorsal setae sometimes missing but sockets always visible, posterior seta longest 0.14–0.16, position of single seta above ventral margin of clypeus 0.5–0.7X total distance from ventral margin to AME. Chelicerae : anterior teeth four right, five left in one male. Eyes : size of eyes varies in diameter but ALE usually the largest followed by PME, PLE generally intermediate between PME and AME, AME smallest separated by a quarter to a half AME diameter, PME–PME 1.2–1.8X PME diameter, AME–ALE 1.0–1.4X AME diameter, lateral eyes contiguous. Sternum : length and width 0.43–0.48. Legs : varying from yellowish orange to pale yellow; TmI 0.45–0.50, TiI l/d 4.7–5.3. Pedipalp : palpal femur 0.63–0.67X length of femur I (mean 0.65) and half the length of carapace. Female s (n=11). Total length 1.6–2.1. Carapace : length 0.71–0.86, width 0.55–0.66, cephalic height 0.30–0.38, clypeal height 0.11–0.13, coloration varying as in males, one or more of the 3 long mid-line dorsal setae sometimes missing but sockets always visible, decreasing in length from posterior to anterior, posterior 0.16–0.21, position of single seta above ventral margin of clypeus 0.60–0.75X total distance from ventral margin to AME. Eyes : variation in diameter and relative size as in males, AME–AME 0.3–0.9X AME diameter, AME–ALE 0.8–1.4XAME diameter, PME–PME 0.7–1.1X PME diameter, PME–PLE 1.2–1.6X PME diameter, PME–AME 1.4–2.0. Sternum : length and width 0.45–0.52. Legs : coloration varies as in males; TmI 0.44–0.55, TiI l/d 4.4–5.2. Epigynum : width greater than length, length/width 0.70–75; under microscope (125X): width of (apparent) horizontal component of median plate varying in length (anterior to posterior), vertical component of median plate with internal carinae usually parallel, occasionally with anterior portion narrower than posterior, spermathecae elliptical, or kidney-bean-shaped (medial surface concave), usually oriented anterolaterally occasionally somewhat less laterally and more dorsally.