Cylisticus ilamicus, Bakhshi & Kashani & Sadeghi, 2020

Bakhshi, Y., Kashani, G. M. & Sadeghi, S., 2020, Cylisticus ilamicus sp. nov., a new woodlouse species (Oniscidea: Cylisticidae) from Iran, Zoosystematica Rossica (China) 29 (2), pp. 316-322 : 317-320

Cylisticus ilamicus sp. nov.

( Figs 1–4)

Holotype: Male, 14 mm, Iran, Ilam Province, Mazhareh Cave , 32°53′N 47°41′E, elev. 953 m, 7.V.2016, H. Darvishnia & Y. Bakhshi leg. , Iso- 1043 ( ZM-CBSU) .

Paratypes: Two males and three females, same data as for holotype ( ZM-CBSU, Iso- 1044) ; two males and one female, same data as for holotype ( PCGMK, 2659) .

Diagnosis. Head with well-developed, broadly rounded median lobe and with prominent lateral lobes; male pereopod VII ischium club-like, merus with slightly concave ventral margin, proximal part equipped with two to three spiny setae.

Description. Maximum length of male 14 mm, of female 15 mm. Colour brown–grey with pale yellowish muscle spots. Dorsal surface of head, pereon and pleon smooth, covered with small triangular scale-setae ( Fig. 3C, D).

Head with broadly rounded median lobe, without longitudinal carina and dorsal edge slightly bent downwards ( Fig. 2A, B); lateral lobes well-developed ( Figs 1B, 2A); eyes with ca. 20 ommatidia. First antenna with three articles, distal one bearing ca. 30 aesthetascs on inner margin ( Fig. 3B). Second antenna long; fifth article of peduncle as long as flagellum, with length to width ratio of 10; flagellum of two articles, distal article slightly longer than proximal one ( Fig. 1D).

Pereon-epimeron I with concave posterolateral margin, hind corner with acute angle ( Fig. 1A). Noduli laterales on pereonite IV almost twice farther from lateral margin than those on epimeron III ( Fig. 1A). Pereopod I ischium triangular, carpus with longitudinal rows of slender scales on rostral surface, dactylus with one dactylar and one ungual seta ( Fig. 1E).

Pleon outline continuous with pereon; pleon-epimeron V with parallel or slightly diverging inner margins ( Fig. 1B). Telson triangular, as long as wide, with concave lateral margins and round- ed apex, surpassing uropod protopodites ( Fig. 3A). Uropod-exopodites short, 0.5 times as long as telson ( Fig. 3A). Pleopod exopodites I–V with partly covered lungs ( Fig. 4A–F).

Male. Pereopods I–VII merus and carpus with brushes of setae, denser in anterior ones ( Fig. 1E– G). Pereopod VI basis with concave ventral side, bearing field of long and dense setae on distal half; ischium with one median and one distal spiny seta on sternal margin ( Fig. 1F, 2C). Pereopod VII ischium elongated, ventrally slightly concave and equipped with hairy brush of small setae and five to six long spiny setae; merus with slight projection

Y. Bakhshi et al. A new species of Cylisticus from Iran in proximal part equipped with two to three spiny setae ( Fig. 1G, 2D). Pleopod exopodite I with short hind-lobe, outer margin sinuous with a row of small setae ( Fig. 4A); endopodite I straight with apical part slightly bent outwards, equipped with some short setae and a small lobe-like extension ( Fig. 4B). Pleopod endopodite II longer than exopodite; exopodite triangular with a row of setae on outer margin ( Fig. 4C). Pleopod exopodites III and IV triangular, outer margin concave bearing a line of setae ( Fig. 4D, E); pleopod exopodite V triangular with a row of setae on outer margin ( Fig. 4F).

Comparison. Unlike the other species of the genus Cylisticus having a longitudinal carina, C. ilamicus sp. nov. possesses a broadly rounded frons ( Fig. 2A), distinguishing the species from other congeners. However, the new species shows all the other characteristics of the genus, namely smooth

Y. Bakhshi et al. A new species of Cylisticus from Iran dorsal surface, short uropod exopodites and the eccentric position of noduli laterales on pereonites IV and VII (though the latter feature is present only in the eastern group; see Schmalfuss, 2003a). The new species is readily distinguished from C. masalicus , the only other known Cylisticus species from Iran, by lacking epistomal carina and by pleopod endopodite I of the male with apex bent outwards.

Etymology. The new species is named after Ilam Province, where Mazhareh Cave, from which the type material was collected, is located.

Habitat. Although the samples examined in this study were collected in completely dark parts of Mazhareh Cave, the species should be considered as a trogloxene, because it does not have the features of the troglophile or troglobite species (reduction or loss of eyes and pigmentation, etc.). Therefore, further surveys outside the cave are necessary to confirm this hypothesis.