Notes on two species of the genus Atemnus Canestrini ( Pseudoscorpiones : Atemnidae ) from China

Acknowledgements: We are grateful to Prof. Mark S. Harvey (Western Australian Museum, Perth, Australia) and Prof. Volker Mahnert (Museum of Natural History, Geneva, Switzerland) for their invaluable comments and many helps on this text. Many thanks are given to Prof. Xin-ping Wang for his generous helps to improve the grammar in this text. This work was supported by the National Natural Science Foundation of China (Nos. 30970325, 31071885, 31093430). The pseudoscorpion family Atemnidae Kishida, 1929 (see Judson 2010) is divided into two subfamilies and 19 genera, with four species and four genera from China (Atemnus Canestrini, 1884, Anatemnus Beier, 1932 and Paratemnoides Harvey, 1991 of the subfamily Atemninae Kishida, 1929 and Diplotemnus Chamberlin, 1933 of the subfamily Miratemninae Beier, 1932). Atemnus Canestrini, 1884 is the type genus of Atemnidae and includes five species: Atemnus letourneuxi (Simon, 1881) from northern Africa and Yemen, A. neotropicus Hoff, 1946 from the Carribean Abstract: Two pseudoscorpion species of the genus Atemnus Canestrini, 1884 are reported from China: A. limuensis sp. nov. from the Ormosia tree bark in a humid tropical forest and A. politus Simon, 1878 from leaf litter in a temperate deciduous forest. A key to all known species of this genus is provided.

region, A. strinatii Beier, 1977 from the Philippines, A. syriacus (Beier, 1955) from Europe and the Middle East, and A. politus (Simon, 1878) widely distributed from Europe and northern Africa to Asia, including China (Harvey 2011).
With support from the National Natural Science Foundation of China, the authors began to collect and study Chinese pseudoscorpions in 2007.Two Atemnus species have been found in our collection, including a new Atemnus species from Hainan, which differs morphologically from other Atemnus species in China and A. politus from Shanxi Province.In this paper, we describe the new species and provide a detailed description of A. politus based on the material from Shanxi, China.

Materials and Methods
The material was preserved in 75% alcohol.The description and terminology follow Chamberlin (1931) and Judson (2007).Terminology of genitalia follows Klausen (2005).All measurements are given in millimetres.Drawings were made with the aid of a prism mounted above the eyepiece of a compound microscope.Photographs were taken with a Leica M165c stereomicroscope.
Detailed examination was carried out with a Nikon YS100 general optical microscope.Temporary slide mounts were made in glycerol.The specimens referred here are deposited in the Museum of Hebei University (MHBU), Baoding City, China.
Remarks: Atemnus, the type genus of Atemnidae, is similar to Anatemnus in having a similar pedipalpal patella, but can be distinguished by the trichobothrial pattern on the fixed finger: the distance between est and esb is the same as that between ist and isb in Atemnus, but longer in Anatemnus.The definition of atemnid genera has long been based on external characters only.Klausen (2005) studied the male genitalia of 44 Atemninae and Miratemninae species and concluded that the present generic delimitation was not reliable.As a result, the male genital structures are also explored, in addition to the external characters.The major differences between the two genera Atemnus and Anatemnus can also be found in the male genital organ (Klausen 2005, p.658, figs 9, 23-25).
Description: Pedipalps and the anterior half of carapace deep brown, tergites yellow (Image 1).Setae on body and legs apically dentate.
Carapace smooth (Fig. 1A), without furrow and longer than broad (1.12 × in male and 1.04-1.07× in female); with distinct eyespots; 38-42 setae in total, of which 6 on anterior margin and 6-8 on posterior margin; the anterior half darker than the posterior half.
Cheliceral hand with four setae, bs and es short and finely dentate, and is and ls long and acute, fixed finger with four retrorse teeth and three small apical teeth, movable finger with a long, tooth-like subapical lobe, male galea (Fig. 1B) relatively short and with six branchelets and female galea (Fig. 1C) long and with 5-6 distinct branchelets, of which the basal one rebranched, serrula exterior 21-25 lamellae, rallum of four setae, only the distal one dentate anteriorly.Pedipalp: trochanter  1E-F); trochanter with distinct round dorsal protuberance, fixed finger (Fig. 1G) with 29-30 cusped marginal teeth, movable finger with 35 marginal teeth, venom duct short, ramosus nodus between trichobothria et and it, but near et.Trichobothrial pattern: st on movable finger nearly between t than sb; on fixed finger distance of est removed from esb same as ist and isb, it from finger tip nearly equals to distance between ist and isb.
Habitat: The specimens of A. politus were collected from leaf litter in a temperate deciduous forest.
Remarks: Atemnus politus was first reported from China by Beier (1967).The male genital structures of the specimens from Shanxi Province fit A. politus illustrated by Klausen (2005).In addition, the dimensions and proportions are rather consistent with those of A. politus given by Beier (1932a, b;1963) and Dashdamirov & Schawaller (1992).Based on the external morphological characters and male genital characters, we believe the material from Shanxi, China belonging to A. politus.
Etymology: The specific name is derived from the type locality.
Diagnosis: This new species can be recognized by the following combination of characters: carapace with two distinct eyespots; body in large size (male 4.38-4.88,female 5.40-6.25);retrolateral face of pedipalpal trochanter, prolateral face of pedipalpal femur and patella, and basal fingers distinctly granulate; dorsal and retrolateral face of trochanter with coniform tubercles; carapace covered with numerous setae.
Description: Pedipalps and the anterior half of carapace reddish-brown (Image 2), tergites brown.Setae on body and legs apically dentate.
Atemnus politus can be easily be separated from A. limuensis sp.nov.by the slimmer male genital organ (Figs.1K, 2K): the ejaculatory canal atrium (e) is not well-developed and may be aberrant in A. politus; but in A. limuensis sp.nov., the atrium is normal, crescent-shaped on either side, and the distal end of the atrium is typically procurved.Moreover, the distal part (l) of lateral apodemes (a) in A. limuensis sp.nov. is larger than that in A. politus.However, they have many congeneric characters in the male genitalia (the letters refer to those of Figs.1K and 2K): (1) the sclerotized distal part of lateral apodemes; (2) the presence of a hooked branch on proximal part of the lateral apodemes; (3) the presence of a rugose darker area on proximal part of the lateral apodemes; (4) the presence of a round projection on medial diverticulum and a prominent extension along the sagittal plane in M-shaped bulge (k) on two medial diverticula; (5) the long and proximally diverging lateral rods; (6) the distally joined long dorsal apodeme; and (7) the presence of bilobed anterior wall on the ventral diverticulum.