Discovery of Hemilepistus elongatus Budde-Lund, 1885 (Isopoda, Oniscidea) in Iran: redescription and intraspecific character variability

Abstract In the present study, Hemilepistus elongatus Budde-Lund, 1885 is reported from Iran for the first time, redescribed and its diagnostic characters are figured. This species reveals a high variability in morphological characters. The division of the species at the subspecific level can not be supported anymore. This species differs from other species of the genus by the unique shape of male pleopod-endopodite I.


Introduction
Budde-Lund (1879) created Hemilepistus as a subgenus of the genus Porcellio Latreille, 1804. Verhoeff (1930) raised it to the generic level and divided it into two subgenera, Hemilepistus and Desertellio, based on absence or presence of a frontal line between the profrons and the vertex. Originating in Central Asia (Schmalfuss 1998), this genus has expanded its geographical distribution to North Africa (Lincoln 1970). Recently, Kashani et al. (2010) reported five species of the subgenus Hemilepistus from Iran and this is the first record of the subgenus Desertellio from this region. According to the species list of Schmalfuss (2003), the subgenus Desertellio includes 10 valid species, namely Hemilepistus buddelundi Borutzky, 1945, H. communis Borutzky, 1945 elongatus Budde-Lund, 1885, H. fedtschenkoi (Uljanin, 1875, H. heptneri Borutzky, 1945, H. nodosus Budde-Lund, 1885, H. pavlovskii Borutzky, 1954, H. ruderalis (Pallas, 1771, H. russonovae Borutzky, 1951 andH. zachvatkini Verhoeff, 1930. Hemilepistus elongatus was described by Budde-Lund (1885) on the basis of one female specimen from Taschburun in "Transcaucasus". Borutzky (1945) reported this species from Caucasus and later he (Borutzky1955) described the new subspecies H. elongatus transcaspius from Turkmenistan. In addition to the above mentioned localities, Röder et al. (1993Röder et al. ( , 1996 and Röder and Linsenmayr (1999) reported this species from Ararat, easternmost Turkey. No record of this species has been reported from Iran. The present study, however, showed that this species has a broad geographical distribution in Iran.
Intraspecific variability of morphological characters has been reported in many terrestrial isopods (e.g. in Oniscus asellus (Bilton 1994), Ligidium spp. (Klossa-Kilia et al. 2006), Porcellio lamellatus (Montesanto et al. 2007), Orthometopon spp. (Poulakakis and Sfenthourakis 2008), Armadillo tuberculatus (Kamilari and Sfenthourakis 2009)). Examination of numerous specimens from different parts of Iran ( Fig. 1) and some other specimens from Caucasus revealed that intraspecific variability is present also in some diagnostic characters of Hemilepistus elongatus. Due to the lack of a comprehensive description along with a critical consideration of subspecific division for the species, the main purposes of the present paper are the redescription of H. elongatus, the demonstration of its character variability and the elucidation of its taxonomic status at subspecific level. Moreover, new records of this species from Iran are presented.

Material and methods
The material of the present study from Iran was collected by the first author unless otherwise mentioned. The specimens were collected by hand and preserved in 96% ethanol. The isopods were dissected and body parts were slide-mounted using Euparal (Carl Roth, Karlsruhe). Digital color images were taken using a Qimaging MicroPublisher 5.0 RTV digital camera and Syncroscopy Auto-Montage (v 5.03.0061) software. Drawings were made using a camera lucida fitted on an Olympus SZX12 dissecting stereomicroscope and on an Olympus BX51 compound microscope. The material used for SEM-preparations was air-dried overnight. The mounted material was coated with gold in a sputter coater to 40 nm thickness and examined with a Hitachi S-2460N SEM.
For comparison, type or additional material was obtained from the Natural History Museum, London (BMNH) and Staatliches Museum für Naturkunde, Stuttgart (SMNS). The examined material from Iran is deposited in the Zoological Museum, University of Tehran (ZUTC). Some specimens are kept in the personal collection of the first author.

Results and discussion
In addition to the presence of H. elongatus in Caucasus, Turkey and Turkmenistan, the present study confirms the occurrence of this species from Iran where it has a broad geographical distribution (Fig. 1) in diverse habitats. This species, like many other terrestrial isopods, shows a high variability in many morphological characters including coloration, size and shape of frons, ratio of flagellar articles, shape of pleotelson, and even in the male secondary sexual structures such as pereiopod VII ischium and pleopod I (see description). This character variability led Borutzky (1955) to propose a new subspecies, H. elongatus transcaspius, for specimens from Turkmenistan. According to the Russian author, this subspecies differed from the typical H. elongatus in the shape of the pleopod-endopodite and exopodite I. Evaluation of numerous specimens from different localities in Iran and Caucasus revealed that various states of these characters are sometimes found within the same population, often with intermediate forms. Though there was no possibility to examine specimens from Turkmenistan, the differences which led Borutzky (1955) to describe a new subspecies, fall within the morphological variability of H. elongatus.
Redescription. Maximum length of both male and female: 18 mm. Body elongated. Color brown with epimera, posterior margin of tergites and pleotelson pale (Fig. 2).
Cephalothorax with rounded lateral lobes, median lobe with variable size and shape; several rounded tubercles of the same or different size in dorsal part (Fig. 3A-D); fron-tal line sinuous in frontal view, with or without incision in the middle; no suprantennal line (Fig. 3E-F); eyes with 20-25 ommatidia. Antenna long, reaching posterior margin of second pereion-tergite; flagellum slightly shorter than fifth article of peduncle, with two articles, first article of equal length or up to 2.5 times as long as second article (Fig.  4A). Antennule of three articles with a tuft of long aesthetascs at apex (Fig. 4B).
Pleopod-endopodite I straight, apex with a leaf-like lobe, equipped with setae, variable in shape (Fig. 5A). Pleopod-exopodite I as in Fig. 5B-F, inner lobe variable in shape. Pleopod-exopodites II-III as in Fig. 5G-H. Remarks. This species is distinguished from other species of the genus by the unique shape of male pleopod-endopodite I, with apex bearing a leaf-like lobe.