Rediscovery of Lobonychiumpalpiplus Roewer, 1938 (Opiliones, Laniatores, Epedanidae) in Sabah, Malaysia

Abstract Lobonychiumpalpiplus Roewer, 1938, originally reported from Indonesian Borneo, is redescribed based on the specimens from Malaysia. The genitalia of this species are described for the first time and a new genital terminology is proposed. The rediscovery expands the known distribution of the species to Malaysian Borneo.


Introduction
The monotypic epedanid genus Lobonychium Roewer, 1938 was previously known from three specimens of the nominate species L. palpiplus Roewer, 1938, collected in the area of Pontianak (Kalimantan Barat, Indonesia, island of Borneo). The species is peculiar in having seven ventral and medial setiferous tubercles on the femur of the pedipalp and basal lobes on the claw of tarsi III and IV. The types are deposited in the Naturmuseum Senckenberg, Sektion Arachnologie, Frankfurt am Main, Germany. Except for the original description, the genus and species have not been mentioned in the literature during the past eighty years.
In February 2017, the senior author was able to re-examine the type specimens. Moreover, Malaysian Borneo, to the north of the type locality, was visited in October 2015 and May 2017 and several specimens (male and female) of L. palpiplus were collected. The newly discovered Lobonychium specimens are redescribed and illustrated.

Materials and methods
Taxonomic methods follow the outline proposed by Acosta et al. (2007). The type material of Lobonychium is preserved in 70% denatured ethanol, and the specimens were examined under a Leica MZ16 at the Senckenberg Museum, Frankfurt, Germany (SMF). Non-type specimens were preserved in 75% ethanol, examined and drawn under a Leica M205A stereomicroscope. Photographs were taken using a Leica M205A stereomicroscope equipped with a DFC450 CCD. The male genitalia were placed first in hot lactic acid, then transferred to distilled water to expand the movable parts for observation (Schwendinger and Martens 2002). The terminology of genital structures follows Macías-Ordóñez et al. (2010), and the macrosetae terminology follows Kury and Villarreal (2015). Non-type material is deposited in the Museum of Hebei University, Baoding, China (MHBU). All measurements are given in mm.
Sexual dimorphism. Tibia II in male distended at distal portion, but normal in female.
Distribution. The type locality is at or near the city of Pontianak ( Redescription. Male (MHBU-Opi-20151208m) habitus as in Figs 1, 8-9, 31. Coloration (Fig. 31): entire body rusty yellow, with somewhat dark brown to blackish brown patches on dorsum; median area of carapace with dark brown reticulations; both lateral ridges of scutum with blackish brown stripes; opisthosomal region of scutum banded with a dark brown outline; a dark brown band across posterior margin of scutum; free tergites I-III each with a dark brown band; coxa with dark brown reticulations; free sternites with transverse dark brown band; chelicerae and pedipalp reticulated; trochanters of all legs pale yellow, femur, patella, tibia and metatarsus with black reticulations, tarsus lighter.
Dorsum (Figs 8,31). Scutum elongate in appearance, both sides straight, nearly parallel, widest portion of body at scutal area IV, abdomen bluntly pointed posteriorly. Carapace unarmed on lateral portion of anterior margin. Surface of dorsum smooth. Ocularium low and oval, unarmed, removed from anterior border of scutum by 0.16 mm. Borders of opisthosomal scutum parallel to each other. Free tergites and anal operculum unarmed.
Venter (Fig. 9). Surface of coxa I tuberculated, antero-dorsally with a coarse tubercle, and a row of five tubercles on ventral surface. Coxa II with a row of small granules on ventral surface. Coxae III and IV nearly smooth aside from a row of small teeth on front and rear margins of coxa III. Genital operculum and free sternites with setatipped granules. Spiracles clearly visible.
Pedipalpi (Fig. 6). Coxa dorsally with one small tubercle near distal margin. Trochanter ventrally with one setiferous tubercle and dorsally with one small tubercle. Femur ventrally with a row of seven setiferous tubercles of even size and spirally arranged from base to distal end on medial side; dorsally with many low conical tubercles along entire length. Patella ventro-mesally with two long and one short setiferous tubercles, and ventro-ectally with one long and one short setiferous tubercles. Tibia ventro-mesally with three setiferous tubercles, and ventro-ectally with four setiferous tubercles. Tarsus with three setiferous tubercles on each side of ventral surface. Tarsal claw curved, approximately same length as tarsus.
Remarks. The three type specimens have not been dissected and are in good condition, with all appendages attached. The original description of the types by Roewer (1938) corresponds more-or-less to the morphology of the type specimens except for few minor characters, e.g., the male tibia II is distended at its distal portion, the  presence of one short setiferous tubercle ventro-mesally on the pedipalpal patella, the minimum numbers of the tarsomeres II and III are 18 and 6, respectively, and the smaller male body (1.89-1.96).
Additionally, the localities of the new records from Malaysia are at most about 120 km apart. The distance between the recorded type locality (Indonesian part of Borneo) and the new localities (Malaysian part) is nearly 1000 km (Fig. 36).
According to the drawings presented by Suzuki (1969: 30, fig. 19 E;1977: 19, fig. 6 F-G;1981: 268, fig. 1B-C) the male genital morphology of Epedanidae seems to be quite homogeneous and little functional variation has been documented to date.