Megachernes afghanicus Beier, 1959: 274–275

Nassirkhani, Mahrad, Received, Reza Vafaei Shoushtari, Online, Published & Version, Final, 2017, Key to the species of Megachernes Beier (Pseudoscorpiones: Chernetidae), with notes on M. afghanicus and M. pavlovskyi, Turkish Journal of Zoology 41 (3), pp. 568-575 : 572-575

Megachernes afghanicus Beier, 1959: 274–275 , fig. 17. Syn. nov.

Material examined. IRAN: Hormozgan Province: 1♀, Geno Protected Area [27°24′35″N, 56°07′16″E, altitude 1800 m], Bandar-e-Abbass, Kurdbasto cave , under stone, 14 April 2015, leg. M. Nassirkhani ( IAUA) .

Measurements in mm (length/width): Carapace: 1.32/1.55. Pedipalp: trochanter 0.76/0.42; femur 1.32/0.44; patella 1.27/0.51; chela (with pedicel) 2.15/0.70; chela (without pedicel) 2.05; hand (with pedicel) L.1.17; movable finger L. 1.05. Leg I: trochanter: 0.29/0.22; femur 0.40/0.23; patella 0.66/0.19; tibia 0.74/0.13; tarsus 0.56/0.11. Leg IV: trochanter 0.59/0.27; femur 0.40/0.21; patella 0.98/0.24; femur + patella 1.27; tibia 1.15/0.15; tarsus 0.76/0.12.

The present key serves for identification of the described species belonging to the genus Megachernes . The key can be used for the identification of females, as well as many males, except those that belong to M. crinitus Beier, 1948 , M. papuanus Beier, 1948 , M. penicillatus Beier, 1948 , and M. queenslandicus Beier, 1948 , which are still unknown. Some species, e.g., M. grandis ( Beier, 1930) , M. titanius Beier, 1951 , and M. barbatus Beier, 1951 may be identified through different key couplets, because there are differences between the types and the subsequently described material. For example, in M. grandis , the specimen collected from Java ( Indonesia) ( Beier, 1948) is distinctly larger than the holotype ( Beier, 1930).

The newly collected female from Iran was attributed to M. afghanicus based on its morphometric and morphological characters ( Figures 1–8 ), especially the pedipalpal femur length. The possibility of synonymy between M. pavlovskyi and M. afghanicus was first mentioned by Dashdamirov (2005).

The original description of M. afghanicus and the published descriptions of M. pavlovskyi show no significant morphometric differences; they can be considered within the variation range of the species; for example, the pedipalpal femur size is 1.01/ 0.40 mm for the Pakistani female ( Dashdamirov, 2005), 0.90–1.20/ 0.28–0.39 mm for the type and the females of M. pavlovskyi reported from Iran ( Redikorzev, 1949; Christophoryová et al., 2013), 1.26/ 0.40 mm for the female type of M. afghanicus ( Beier 1959) , and 1.32/ 0.44 mm for the newly collected female from Iran.

There were no obvious differences between the cheliceral morphology ( Figure 1 ) of M. pavlovskyi and M. afghanicus ; the cheliceral hand bears 7 setae (♀), the rallum contains 3 blades, and the serrula exterior consisted of 23–24 blades in M. pavlovskyi and 21 blades in M. afghanicus ( Redikorzev, 1949; Beier, 1959; Dashdamirov, 2005; Christophoryová et al., 2013). The serrula exterior of the newly collected specimen from Iran consisted of 24 blades.

The posterolateral corner of pedal coxae IV ( Figure 2 ) was described as an enlarged and rounded lobe for both species ( Redikorzev, 1949; Beier, 1959; Christophoryová et al., 2013), as is the case for all species of the genus. The position of the tactile seta on pedal tarsus IV has been reported as occurring in the middle of the segment in M. pavlovskyi ( Christophoryová et al., 2013) and M. afghanicus ( Beier, 1959) , but it is situated slightly proximal to the middle in the new specimen from Iran ( Figure 3 ).

The shape of the spermatheca is an important generic characteristic for this genus, but was not described for M. afghanicus by Beier (1959). Based on the newly collected female from Iran, it is T-shaped, extremely elongated, and slightly expanded terminally ( Figure 4 ), as described for M. pavlovskyi by Christophoryová et al. (2013).

Noticeably, the trichobothrial positions on the fixed chelal finger showed slight variation in the 2 species, with the trichobothrium isb located distinctly proximal to est (judging from Schawaller and Dashdamirov, 1988: fig. 62), or slightly distal to isb (judging from Dashdamirov and Schawaller, 1992: fig. 12e; Dashdamirov, 2005: fig. 188) in M. pavlovskyi , while in M. afghanicus , trichobothrium isb is located at the same level as est in the male and slightly proximal to est in the female (judging from Beier, 1959: fig. 17; Figures 5 and 6 ).

The movable chelal finger of the types of M. afghanicus possesses 4–5 prolateral accessory teeth ( Beier, 1959), whereas the newly collected specimen from Iran has 6 such teeth ( Figure 7 ). In M. pavlovskyi , there were 8–11 such teeth in the adults from Iran ( Christophoryová et al., 2013), and 5 on the female from Pakistan ( Dashdamirov, 2005). It appears that the chelal accessory teeth may vary within a species and thus cannot be considered as an important character for distinguishing the species.

The pedipalpal setation ( Figures 5 and 8 ) differs slightly between the 2 species; e.g., in the male type of M. afghanicus , the pedipalpal femur is covered by long setae, and the patella and chelal hand are covered with shorter setae than those on the femur (judging from Beier, 1959: fig. 17). A similar setae pattern was reported on the male of M. pavlovskyi (judging from Schawaller and Dashdamirov, 1988: fig. 62; Christophoryová et al., 2013: fig. 3B). In the females of both species, all pedipalpal segments are covered by short dentate setae (judging from Beier, 1959: fig. 17; Dashdamirov, 2005: fig. 188; Figures 5 and 8 ). The presence of grouped short setae at the base of the fixed chelal finger in dorsal view (judging from Beier, 1959: fig. 17; Dashdamirov, 2005: fig. 188; Figure 5 ) is another similarity between the species.

Duetotheabsenceofdistinctmorphologicaldifferences especially with respect to the chelal shape, the pedipalpal setation, the structure of the chelicerae and spermatheca, and the shape of the posterolateral corner of leg IV, the presence of small and undetermined differences in size, and also the possibility of trichobothrial pattern variation within the species, M. afghanicus is here considered as a new junior subjective synonym of M. pavlovskyi .

Nomenclatural acts

This work and the nomenclatural acts it contains have been registered in ZooBank. The ZooBank Life Science Identifier ( LSID) for this publication is: http://zoobank. org/lsid:zoobank.org:pub: 242300E6-9DCD-4462-A9F8- 24786EC1DAEB.

Figures

Figures 1–4. Megachernes pavlovskyi Redikorzev, 1949, ♀: 1- chelicera, lateral aspect (showing rallum, galea, and setae on hand); 2- left pedal coxae, ventral aspect (showing posterolateral corner of coxa IV); 3- pedal tarsus IV; 4- spermatheca.

Figures 5–8. Megachernes pavlovskyi Redikorzev, 1949, ♀: 5- right pedipalpal chela, retrolateral dorsal aspect (granulation pattern not shown completely); 6- left pedipalpal chela, ventral aspect; 7- chelal fingers, ventral aspect (showing internal accessory teeth); 8- basal segments of pedipalp, dorsal aspect (granulation pattern not shown completely).