Schizidium shidokhtae, Ahdiyeh & Alireza & Ghasem, 2025

Schizidium shidokhtae sp. nov.

Figures 2A–E View FIGURE 2 , 3 View FIGURE 3 , 4 View FIGURE 4

Material examined. Holotype: male, 7 mm, Semnan Province, Shahrood to Azadshahr road, 88 km to Azadshahr , 36° 45. 26´N, 55° 17. 23´E, alt. 1680 m, 2 May 2024, leg. A. Abedini ( ZUTC 70146 ). GoogleMaps

Paratypes: same data as holotype, thirteen males, twenty females ( ZUTC 70147 ) GoogleMaps ; same data as holotype, two males, two females ( PCGMK 3305 ) GoogleMaps .

Diagnosis. Head with continuous frontal ridge; conspicuous coloration with yellowish patches on mid-dorsal part of pereonites 1 and 4–7; schisma with inner lobe slightly shorter than outer one; pereopod 7 basis wide; male pleopod exopodite I with short triangular hind lobe.

Description. Maximum body length: male 7 mm, female 11 mm.

Coloration: Gray or dark brown, mid-dorsal part of pereonites 1 and 4–7 as well as pereon-epimera 1, pleonepimera, uropods and distal part of telson yellowish ( Figs 2A–B View FIGURE 2 ).

Body convex, tergites smooth; head with continuous frontal ridge ( Fig. 2C View FIGURE 2 ); antennule with three articles; antenna flagellum bearing two articles, distal one more than twice as long as proximal one (fig. 3A). Schisma with inner lobe slightly shorter than outer one ( Fig. 2D View FIGURE 2 ). Pereopod 1 ischium almost triangular, carpus with a brush of setae on rostral surface ( Fig. 3B View FIGURE 3 ). Telson triangular, its width as wide as long, with slightly concave sides and rounded apex; uropod-exopodite flattened, filling gap between distal part of pleonite 5 and telson ( Fig. 2E View FIGURE 2 ). Male: pereopod 1–7 merus and carpus with a dense brush of setae on ventral margin; pereopod 7 basis very wide; ischium triangular with a completely straight ventral surface bearing fine setae, with a ring of long setae on distal margin ( Figs. 3C, D View FIGURE 3 ). Pleopod endopodite 1 long with straight and pointed apex ( Fig. 4B View FIGURE 4 ); exopodite with short triangular distal lobe bearing several scattered long setae ( Fig. 4A View FIGURE 4 ). Pleopod endopodite 2 slightly longer than exopodite with very thin distal part; exopodite triangular with deeply concave outer margin bearing several scattered setae ( Fig.4C View FIGURE 4 ). Pleopod exopodites 3–5 with concave outer margin bearing two to three rows of setae; hind lobes tapering posteriorly ( Figs. 4D–F View FIGURE 4 ).

Etymology. This species is named in honor of Professor Shidokht Hosseinie (Ostavani) of the University of Shiraz for her many years of contributions to zoological studies in Iran, primarily on arthropods.

Distribution. Northern Iran

Discussion. In recent years, several contributions have been conducted on the terrestrial isopods of Iran, increasing our knowledge on these taxa, but much more works still needs to be done. While molecular approaches have been revolutionized the species delimitation almost in all groups of animals including terrestrial isopods; morphological characteristics are still reliable and used extensively in this regard ( Padial et al. 2010). In fact, species delimited morphologically provide a foundation for further studies on other aspects of their biology. In the case of terrestrial isopods including the genus Schizidium , besides the male secondary sexual characters, different somatic features have been used to discriminate species ( Schmalfuss 2005, 2008; Dimitriou et al. 2023). In this regard, we observe that S. shidokhtae sp. nov. is somewhat similar to S. persicum and appears to have a restricted distribution in the southern range of the latter species (fig. 1). While the pattern of coloration in the members of S. persicum is very similar throughout its geographical range, the new species exhibit a markedly different pattern of coloration, making the distinction of the two species very easy. Additionally, the inner lobe of schisma in the new species is slightly shorter than the outer one, whereas it is conspicuously longer in S. persicum ( Schmalfuss 1986) . The new species is distinguished from all Schizidium species reported from Greece, Cyprus and SW Turkey by having telson with a rounded apex (vs. truncate apex). Moreover, it differs from the species reported from the neighboring countries in having the male pleopod 1 exopodite with triangular distal lobe (vs. a rounded distal lobe in S. davidi (Dolfuss, 1887) and S. rausi ( Schmalfuss, 1988) and head with continuous frontal ridge (vs. interrupted in S. golovatchi Schmalfuss, 1988 ) (see Schmalfuss 1988).