Euryeidon consideratum Dankittipakul & Jocqué, in Dankittipakul & Jocqué, (2004: 764), figs. 38-40 (description of female).

Male (HUST-2018-ZOEC001) (Fig. 1A–C and Fig. 2A). Total length 6.87; prosoma 3.33 long, 2.21 wide, 2.05 high; opisthosoma 2.87 long, 2.30 wide. Eye sizes and interdistances: AME 0.16, ALE 0.18, PME 0.14, PME 0.16, AME–AME 0.08, AME–ALE 0.33, PME–PME 0.11, PME–PLE 0.37. MOQL 0.44; MOQA 0.38, MOQP 0.39. Leg formula 4123; measurements: I 6.75 (1.86, 0.78, 1.50, 1.35, 1.26), II 5.93 (1.65, 0.80, 1.25, 1.20, 1.03), III 5.82 (1.64, 0.77, 1.11, 1.43, 0.87), IV 7.77 (2.07, 0.72, 1.59, 2.11, 1.28). Spination: Fe Ⅰ d11 Ⅱ d11 Ⅲ d111 Ⅳ d111; Pa Ⅲ p1 Ⅳ p1; Ti Ⅰ v222 Ⅱ v222 Ⅲ p111 d111 r111 v2112 Ⅳ p111 d111 r111 v2112; Mt Ⅰ v222 Ⅱ v222 Ⅲ p112 r112 v122 Ⅳ p112 r112 v122.

Figure 1.  

Habitus of Euryeidon consideratum, male (HUST-2018-ZOEC001, A–C) and female (HUST-2018-ZOEC002, D–F) A, D Dorsal view; B, E Ventral view; C, F Lateral view. Scale bars: 1 mm (equal for A–C, equal for D–F).

Figure 2.  

Frontal views of prosoma of Euryeidon consideratum. A Male (HUST-2018-ZOEC001); B Female (HUST-2018-ZOEC002). Scale bars: 1 mm.

Shape and colouration pattern (Fig. 1A–C and Fig. 2A). Carapace oblong, surface rough, covered with short fine hairs in cephalic area; deep brown, without pattern; in profile strongly domed, highest just in front of longitudinal fovea; cervical groove and radial grooves indistinct, fovea represented by a distinct, longitudinal pit. Chelicerae red wine-coloured, with two promarginal teeth and without retromarginal teeth. Labium triangular, reddish-brown, apically with narrow membranous area and anteromedian scopula, basal and lateral margins distinctly darker. Chilum single sclerite, triangular, elevated and smooth. Endites nearly trapeziform, slightly curved, reddish-orange, proximallly distinctly darker, distally distinctly lighter. Sternum 1.37 long, 1.18 wide, coloured as chelicerae, shield-shaped, pre- and intercoxal triangular sclerites present, anterior margin slightly procurved, with two small indentations at level of labium corner, posterior margin protruding. Legs yellowish-brown, but dark brown on femora. Pedicel cylindrical, weakly sclerotised, relatively short, yellow-brown. Opisthosoma round; dorsum of opisthosoma dark brown, with distinct, oval scutum nearly covering the entire length of the abdomen; laterally with three diagonal, flesh-coloured streaks; venter with two diagonal, flesh-coloured wide streaks. Spinnerets yellowish.

Palp (Fig. 3A–D and Fig. 4A–E). Tibia short, cup-shaped, ca. 1/3 cymbium length, with retrolateral apophysis (RTA) arising retrodistally; RTA deeply bifid, with ventral branch (vRTA) and dorsal branch (dRTA), both vRTA and dRTA being heavily sclerotised, claw-shaped, slightly curved and tapering, apex sharp; dRTA distinctly long, longer than tibia, ca. 2/5 cymbium length, extending to cymbial fold, vRTA relatively shorter, ca. 1/2 dRTA length. Cymbium (Cy) drop-shaped, approximately 1.45 times as long as wide, retrolateral margin with distinct bulge (CB), with pro- (PCE) and retro-basal (RCE) extensions, respectively; PCE distinctly smaller, digitiform, ca. 1/10 cymbium length; RCE as long ridge running along retro-basal margin of cy, ca. 2/5 cy length; cymbial fold (CF) approximately 1/3 length of cymbium (Cy). Tegular apophysis (TA) spatula-like, approximately 1/3 length of tegulum; proximally paler, slightly thicker and curved; medially slender; distally heavily sclerotised and widened, with a flattened apex. Conductor (C) roughly cylindrical; proximal part partly membranous; apical part sclerotised, as a subtriangular flange, apex blunt. Embolus (E) filiform, arising pro-basally at approximately 7–8 o’clock position, curving clockwise along the tegular margin, ending at ca. 1 o’clock position; embolus base (EB) basally with protruding conical extension.

Figure 3.  

Male palp of Euryeidon consideratum (HUST-2018-ZOEC001). A Ventral view; B Dorsal view; C Prolateral view; D Retrolateral view. Scale bar: 0.2 mm (equal for A–D). Abbreviations: C, conductor; CB, cymbial bulge; CF, cymbial fold; Cy, cymbium; DB, dorsal bugle of cymbium; dRTA, dorsal branch of RTA; E, embolus; EB, embolic base; ET, embolic tip; PCE, prolateral cymbial extension; RCE, retrolateral cymbial extension; TA, tegular apophysis; vRTA, ventral branch of RTA.

Figure 4.  

Male palpal tibia of Euryeidon consideratum (HUST-2018-ZOEC001). A Ventral view; B Dorsal view; C Prolateral view; D Retrolateral view; E Anterior view. Scale bar: 0.2 mm (equal for A–E). Abbreviations: dRTA, dorsal branch of RTA; vRTA, ventral branch of RTA.

Female (Fig. 1D–E and Fig. 2B). Total length 7.45; prosoma 4.73 long, 2.95 wide; opisthosoma 4.21 long, 3.30 wide, 1.89 high. Eye sizes and interdistances: AME 0.13, ALE 0.15, PME 0.16, PME 0.14, AME–AME 0.07, AME–ALE 0.49, PME–PME 0.16, PME–PLE 0.62. MOQL 0.47; MOQA 0.34, MOQP 0.46. Sternum 1.50 long, 1.25 wide. Leg formula 4123; measurements: I 7.14 (1.97, 0.82, 1.58, 1.40, 1.37), II 6.51 (1.81, 0.9, 1.32, 1.35, 1.13), III 6.30 (1.69, 0.91, 1.12 1.59, 0.99), IV 8.50 (2.23, 0.88, 1.71, 2.3, 1.38). Spination: femora Ⅰ d11 Ⅱ d11 Ⅲ d111 Ⅳ d111; patellae Ⅲ p1 Ⅳ p1; tibiae Ⅰ v222 Ⅱ v1112 Ⅲ p11 d112 r11 v212 Ⅳ p11 d112 r11 v212; metatarsi Ⅰ v222 Ⅱ v222 Ⅲ p111 r111 v112 Ⅳ p111 r111 v112.

Pattern and colouration (Fig. 1D–E and Fig. 2B). As in males, but body slightly paler (see Dankittipakul and Jocqué (2004) for additional details).

Epigyne (Fig. 5A–C). Epigynal area sclerotised, ca. twice wider than long. Atrium (A) elongate arch-shaped, ca. 1/5–1/6 epigynal width and 9/10 epigynal length, slightly widened anteriorly; median plate absent. Copulatory openings (CO) indistinct, located anterolaterally under atrial arch. Lateral border (LB) subtriangular, nearly as long as wide, terminally blunt about 80 degrees. Spermathecae (SP) tubular, strongly convoluted, stacked in piles on each side, with thin fertilisation ducts terminally. Anterior transverse (TB) hyaline, arch-shaped.

Figure 5.  

Epigyne of the female of Euryeidon consideratum (HUST-2018-ZOEC002). A Epigyne, intact, ventral view; B Epigyne, cleared, ventral view; C Vulva, cleared, dorsal view. Scale bar: 0.2 mm (equal for A–C). Abbreviations: A, atrium; CO, copulatory opening; LB, lateral border; Sp, spermatheca (dashed line showing schematic course of spermatheca, dorsal); TB, transverse band.

Males of E. consideratum resemble those of E. sonthichaiae in the general shape of the male palp. The palps of the two species share the absence of dorsal tibial apophysis and by the deeply divided retrolateral tibial apophysis (RTA) with dorsal branch (vRTA) distinctly longer than ventral branch (vRTA) (Fig. 3A–D, Fig. 4A–E; Dankittipakul and Jocqué (2004): fig. 36) (vs. dorsal tibial apophysis present, RTA not divided, such as in E. anthonyi, E. dian, E. monticola or RTA bifurcated, but both branches with similar length, such as in E. musicum; Dankittipakul and Jocqué (2004): figs. 14, 23 and 31; Lu et al. (2023): figs. 2B and C). Males of E. consideratum can be recognised from E. sonthichaiae by: (1) dRTA longer than palpal tibia, ca. 2/5 cymbium length, extending to cymbial fold (vs. shorter than palpal tibia, ca. 1/10 cymbium length) (cf. Fig. 3A, B, D, Fig. 4A–D and Dankittipakul and Jocqué (2004): fig. 36); (2) tegular apophysis (TA) distinctly curved, with widened apex pointing ventrally and not extending beyond the retrolateral margin of cymbium in ventral view (vs. moderately curved, with tapered apex pointing ventro-retrolaterally and extending distinctly beyond retrolateral margin of cymbium in ventral view) (cf. Fig. 3A and Dankittipakul and Jocqué (2004): fig. 35). Females of E. consideratum can be easily distinguished from those of all other congers, with the exception of E. dian, by their epigynes without median plate (Fig. 5A, B and Lu et al. (2023): fig. 1E) (vs. median plate with variable shapes, but present, such as in E. anthonyi, E. monticola, E. musicum and E. schwendingeri; Dankittipakul and Jocqué (2004): figs. 15, 26, 33 and 41), but can be separated from the latter by the elongated arch-shaped atrium (vs. cordiform) (cf. Fig. 5A, B and Lu et al. (2023): fig. 1E), the lateral borders not touching each other (vs. touching) (cf. Fig. 5A, B and Lu et al. (2023): fig. 1E) and by the tubular spermathecae (vs. round) (cf. Fig. 5C and Lu et al. (2023): fig. 1F).

China (Yunnan, new record), Thailand. The new collections extend the known range of this species by ~ 320 km to the northwest (Xishuangbanna) from the type locality (Doi Luang National Park) (Fig. 6).

Figure 6.  

Distribution records of Euryeidon consideratum.

The specimens were collected in leaf litter.

Dankittipakul and Jocqué (2004) noted 'females have a simple epigyne with a median plate of variable shape' as one of the diagnostic characteristics of the genus Euryeidon. In their original paper, all species described, except for E. consideratum, exhibited this feature in females (Dankittipakul and Jocqué (2004): figs. 15, 26, 33 and 41). To address this discrepancy, Dankittipakul and Jocqué (2004) suggested that the median plate of E. consideratum was 'broken off' rather than absent, based on observations of the holotype female. In the present study, we examined five female specimens of E. consideratum, all of which, like the holotype, lacked a median plate. We propose that this structure is likely absent inherently rather than broken off in these specimens. Additionally, the recently-described species E. dian also lacks a median plate in its epigyne (Lu et al. (2023): fig. 1E), demonstrating that the median plate is not a synapomorphic feature of the genus.