Raveniola niedermeyeri from Iran: redescription and new data on distribution (Araneae, Nemesiidae)

Abstract Raveniola niedermeyeri (Brignoli, 1972), a poorly known species, is rediagnosed and redescribed from the types and from recently collected material from northern and central regions of Iran. This species differs from its congeners in having the male embolus curved distally, as well as in the unique conformation of the spermathecae. New data on the distribution of Raveniola niedermeyeri in Iran are also provided.


Introduction
Nemesiidae is the second largest mygalomorph family, containing 350 species (Platnick 2010) and is distributed worldwide. Th e diplurid Brachythele niedermeyeri was fi rst described by Brignoli (1972) on the basis of a few mygalomorph specimens from Iran collected in the vicinities of Astrabad (now called Gorgan) by Oskar Niedenmeyer prior to World War I . Later, this species (hitherto known only from the type locality) and its closest relatives were transferred to the nemesiid genus Raveniola Zonstein, 1987(Zonstein 1987, which currently contains 19 species mainly distributed in the Middle East and Central Asia (Platnick 2010). Th e original description by Brignoli contains some data interpreted erroneously. Th is species was presented as the largest nemesiid of Eurasia, with a carapace length of up to 10 mm in males and 15 mm in females (actually it was found to be considerably smaller), but the leg measurements of the male holotype given in the same paper were disproportional, amounting to less than half of that necessary to correspond to the stated carapace length (see Brignoli 1972). Th e original fi gures showing the confi guration of the male palp and the spermathecae of R. niedermeyeri (Brignoli 1972: fi gs 1-2) are too schematic to permit reliable identifi cation and diff erentiation from its congeners. Th ese incorrect and incomplete data are corrected in our redescription and new data on the distribution of R. niedermeyeri are provided.

Material and methods
Specimens from the following institutions were studied: MHNG -Muséum d'histoire naturelle, Genève, Switzerland; TAU -Zoological Museum, Tel Aviv University, Israel; ZMMU -Zoological Museum of the Moscow State University, Russia.
Photographs were taken either using a Canon 500D digital camera with a 100 mm Canon macro lens and a Zeiss Discovery V20 stereomicroscope with a Canon PowerShot G9 digital camera attached to it. Measurements were taken through a Leica MZ12 stereomicroscope with an accuracy of 0.025 mm (approximated up to the nearest centesimal). All measurements are given in millimetres, except for eye diameters and interdistances which are given in microscope scale units (measured at 100×). Lengths of palps and legs are given as: total (femur, patella, tibia, metatarsus, tarsus).
Redescription. Male (holotype). Total body length including chelicerae 13.80. Colour in alcohol: carapace, chelicerae, palps and fi rst pair of legs dorsally intense reddish brown; eye tubercle with darker spots surrounding AMEs and lateral eyes; sternum, labium, maxillae and legs II-IV light reddish brown; abdomen dorsally light greyish brown; typical darker dorsal pattern consisting of a longitudinal median spot crossed by a few poorly preserved transverse fasciae, ventral abdominal surface and spinnerets pale greyish brown.
Female (paratype): Total body length including chelicerae 15.90. Colour in alcohol and pubescence as in male, dorsal abdominal pattern better preserved, consisting of numerous irregularly arranged, small yellowish brown spots on darker brown background.
Variability. Carapace length in males varies from 5.05 to 5.90; in females from 5.10 to 7.05. Th e general coloration is usually the same as shown in Figs 1 and 2, with insignifi cant variation throughout the series of specimens examined. In males, variations in the shape of the bulb and embolus were not evident. Two variants of the female spermathecae, which diff er only slightly, are shown in Figs 8 and 9.