Psechrus khammouan Jäger, 2007

Bayer, Steffen, 2014, Seven new species of Psechrus and additional taxonomic contributions to the knowledge of the spider family Psechridae (Araneae), Zootaxa 3826 (1), pp. 1-54 : 14-15

Psechrus khammouan Jäger, 2007

Figs 6 , 28 C, 31C

Psechrus khammouan Jäger 2007: 47 , figs 54–67 (Description & illustration of ♂ and ♀). Bayer 2012: 59 , figs 28a–d, 29a–e, 82b, 85e, 88e, 91e (Description & illustration of ♂ and ♀).

Material examined (2 ♀, 4 juveniles): LAOS: Khammouan Prov.: Ban Kouanphavang , 17°27'09''N, 104°56'19''E, ca. 180 m, in cave, P. Jäger leg. 24.– 25.II.2012, ♀ ( SB 1250 ), SMF 63849 . Ban Tathot, 2.5 km WNW of the village, Tham Kamouk Limestone Cave , entrance 17°37'54''N, 105°07'30''E, exit 17°38'00''N, 105°07'12''E, ca. 200 m, entrance area and inner part of cave, P. Jäger leg. 26.IV.2012, ♀ ( SB 1255 ), 4 juveniles ( SB 1251–1254 ), SMF 63850 .

Taxonomic remarks. The females examined in the present study have corresponding spination-patterns, cheliceral dentition, colouration and their measurements are within the limits of the size spectrum listed in Bayer (2012). However, there is significant variation in female copulatory organs with different structures/different orientation of structures of the vulva, as mentioned and discussed in Bayer (2012, p. 62). The present material was useful in the assessment of the overall extent of this variation. SB 1255 from Tham Kamouk (Ban Tathot area) ( Figs 6 , 28 C, 31C) was examined in the present study. Tham Kamouk is ca. 35–40 km northeast of the type locality of P. khammouan (area of Thakek). The position of the spermathecal heads and the direction of the initial part of the copulatory duct of SB 1255 (namely from lateral with a slight incline to antero-medial) are very similar to those of females from the Thakek area as illustrated in Bayer (2012, fig. 29d). From the Ban Tathot area, in particular from Tham Kamouk, Bayer (2012) only recognised females with differently positioned spermathecal heads ( Bayer 2012, fig. 29b) and differently directed initial part of the copulatory duct (namely from anterio-lateral with a decline to medial). If the above-mentioned different forms of females represented two different species, they would not appear syntopically at the same spot within the same cave (according to the competitive exclusion principle). Consequently, SB 1255 provides the evidence that these different vulva character states in all likelihood represent intraspecific variation. Thus, the present results corroborate the notion of Bayer (2012) in treating these different character states of the vulva as intraspecific variation of P. khammouan and rejecting the possible existence of two different species in the area of Thakek on one hand and in the area of Ban Tathot on the other hand. Unfortunately, to date, no males have been recorded from the region of Ban Tathot.

Intraspecific variation of female copulatory organs. In some specimens ( Fig 6 A, 28C) the anterior part of the median septum may be broader than in others (e.g. Jäger, 2007, fig. 57; Bayer, 2012, fig. 29a). The direction of the initial part of the copulatory duct may be from the lateral with a slight incline to the anterio-medial ( Fig. 6 B; Bayer 2012, fig. 29d) or from the anterio-lateral with a decline to the medial ( Bayer 2012, fig. 29b). The positions of the spermathecal heads may differ ( Fig. 6 B cf. Bayer 2012, fig. 29b cf. Bayer 2012, fig. 29d).

Distribution. Laos.

Figures

FIGURE 6. Psechrus khammouan, female SB 1255, SMF 63850 from Ban Tathot, Khammouan Prov., Laos: copulatory organ. A. Epigyne, ventral view. B. Vulva, dorsal view. CD: Copulatory duct; SB: Spermathecal base; SH: Spermathecal head.

FIGURE 28. Psechrus spp., photographic images of epigynes, ventral view. A. Psechrus norops. B. Psechrus rani. C. Psechrus khammouan. D. Psechrus arietinus sp. nov.. A. SB 1270, SMF 64092, from Fraser’s Hill, Pahang Prov., Malaysia. B. SB 1231, MHNG, from Ba Vi, Ha Noi Prov., Vietnam. C. SB 1255, SMF 63850, from Ban Tathot, Khammouan Prov., Laos. D. Holotype (SB 1189, AMNH) from Tra My, Quang Nam Prov., Vietnam.