Ctenolepisma (Sceletolepisma) sagartianum Molero, Kahrarian & Gaju

Kahrarian, Morteza, Molero, Rafael & Gaju, Miquel, 2016, The genus Ctenolepisma (Zygentoma: Lepismatidae) in Western Iran, with description of three new species, Zootaxa 4093 (2), pp. 217-230 : 221-225

Ctenolepisma (Sceletolepisma) sagartianum Molero, Kahrarian & Gaju , new species

Figs. 10‒20

Type material. Holotype: one male from Tag-e Bostan Mount, under rocks, (N34°23’ E47°07’, elev. 1488 m) Kermanshah County, Kermanshah, Iran, June, 2013 (Ref. MNCN: Cat. Types N. 2606, mounted on a slide). Paratypes: one female from Tag-e Bostan Mount, in the ashes and remnants of burnt grass, (N34°23’ E47°07’, elev. 1488 m), Kermanshah County, Kermanshah, Iran, October, 2013 (UCO, Ref. Z2499); 4 males and 2 females (one mounted on a slide) from Bistoon Mountain, under rocks, (N34°23’ E47°26’, elev. 1116 m), Harsin County, Kermanshah, Iran, November, 2013 (UCO, Ref. Z2500); 1 male and 2 females from the same locality and date (UCO, Ref. Z2501) and 1 female from the same locality, June, 2013 (UCO, Ref. Z2502). All specimens deposited in UCO, except the holotype, which has been deposited in MNCN.

Description. Body length up to 6.7 mm. Males with a length greater than 5 mm and females longer than 5.5 mm considered to be adults. Shape of the body subcylindrical, with the thorax very slightly wider than the abdomen base. Epidermal pigment brownish in specimens preserved in ethanol, more intense on appendages. Macrosetae hyaline to brown-yellowish. Dorsal scales with dark pigment. Some scales of the lateral parts of the nota larger than the rest, others showing an indentation corresponding with bare spots ( Fig. 10 ).

Setation of the head and eyes typical of the genus. Antennae broken (maximum length preserved: 3.5 mm). Apical article of maxillary palp about 6 times longer than wide and as long as the penultimate article ( Fig. 11 ). Distal article of labial palp approximately 1.2 times longer than wide, with three sensory papillae arranged in a single row ( Fig. 12 ); low number (usually 2) of isolated sensilla.

Median brush of the anterior margin of the pronotum with 2‒3 rows of macrosetae; anterolateral row with 6‒8 short, smooth (or not clearly plumose) setae. All nota with 6‒8 lateral combs with 1–5 (usually 3‒4) associated macrosetae and 2 posterolateral combs with 4 macrosetae. Some macrosetae of the lateral combs very long, nearly as long as half the length of a thoracic segment.

Anterior trichobothrial areas of the pronotum and mesonotum situated on lateral comb N-2 (antepenultimate). Anterior trichobothrial areas of the metanotum associated with comb N-1 (penultimate). Posterior trichobothrial areas of the nota associated with the last lateral combs (N).

Prosternum subtriangular, as long as wide at its base, with marginal setae in its posterior part, occupying nearly half the length of the lateral margins; row of thin, long setae in each anterolateral corner. This sternite bearing 2‒3 + 2‒3 combs of macrosetae, irregularly and asymmetrically arranged. Each comb with 2‒8 macrosetae ( Fig. 13 ). Mesosternum length about 1.3 times greater than that of the prosternum; the marginal setae inserted only in the apical part, at about a quarter of the length of the lateral sides; 2‒3 pairs of combs with 2‒7 macrosetae each ( Fig. 14 ). Metasternum clearly shorter than wide at its base (ratio length/width about 0.81), with two pairs of lateral combs of 5‒8 macrosetae ( Figs. 15, 16 ). Distance between the antedistal combs about 2.7 times the width of a comb. Hind margin of all thoracic sternites convex, relatively acute in the prosternum and mesosternum and only very slightly truncated in the metasternum.

Protibiae 2.9‒3 times longer than wide; mesotibiae 3.2‒3.3 times longer than wide and 1.2 times longer than protibiae; metatibiae 3.9‒4 times longer than wide and 1.65 times longer than protibiae. Apart from the usual setae, tibiae with plumose macrosetae as follows: on tibia I and II, 3 dorsal and 4 ventral, and on tibia III 3 dorsal and 6 ventral (see Fig. 17 ); all macrosetae shorter than the diameter of the article. Tibiae without scales, those of the femora rounded.

Urotergite I with 1+1 bristle-combs. Urotergites II–VII with 3+3 combs; urotergite VIII with 2+2 combs. Sublateral and lateral bristle-combs with 4‒6, infralateral combs with 5‒7 macrosetae. Urotergite X trapezoidal, with 1+1 combs of 6 macrosetae, the trapezoidal process with a straight hind margin; ratio length/width at the base about 0.37 ( Fig. 18 ). Urosternite I without setae, III–VIII each with 1+1 lateral bristle-combs with 8‒10 macrosetae; urosternites II‒VI each with a submedian comb bearing 6‒9 macrosetae.

Two pairs of abdominal styli; second pair present in specimens longer than 6 mm. In males, inner process of the coxite IX about as long as wide at its base and 4 times longer than the outer process ( Fig. 19 ). In female, inner process of coxite IX length equal to width up to 1.1 times longer than wide at its base and 4 times longer than the outer process. Ovipositor with 32‒33 divisions, apex surpassing tip of the inner process of coxite IX by 1.4 times their length ( Fig. 20 ). Styli long; styli of segment VII 1.4 times longer than the inner process of coxite IX (in a female 6.5 mm long), coxites IX 3 times longer than inner process of the coxite. Ovipositor relatively short, not surpass stylus apex. Apices of gonapophyses rounded and unsclerotized. Caudal filaments broken; maximum length preserved in a cercus, 3.5 mm; in a paracercus, 4 mm.

Etymology. The specific name of this new taxon refers to the Sagartians, an ancient tribe that lived on the Iranian Plateau.

Discussion. Ctenolepisma (Sceletolepisma) sagartianum n. sp. belongs to the subgenus Sceletolepisma sensu Irish (1987) due to the presence of median combs of macrosetae on the urosternites. The redefinition of Sceletolepisma and the split of the genus proposed by Kaplin (1993) is not accepted, according to Irish (1996) and in accordance with our personal and partially published studies (Molero et al. 2010; Molero et al. 2012).

The new species belongs to the “villosa” group within the subgenus Sceletolepisma as defined by Irish (1987) in bearing median combs of macrosetae on urosternites II‒VI, no macrosetae on urosternite I, and urosternite II with only median combs.

The “villosa” group is widespread in Africa and Eurasia, with more than 20 species, but only three share the following characteristics: 3+3 combs on urotergites II‒VII, 3 sensory papillae in the distal labial palpomere and the absence of a transverse comb on coxite IX. Ctenolepisma sagartianum n. sp. is compared primarily with these three species: C. africanellum Wygodzinsky, 1955 from South Africa, C. guanche Mendes 1993 from Gomera, Canary Islands and C. kervillei Silvestri, 1911 , described from Egypt and also reported from Syria (and probably Iraq but not Iran, as discussed below).

C. guanche has only one pair of metasternal combs, while C. sagartianum n. sp. has two pairs. The urosternal combs of C. guanche bear fewer setae, the inner process of the coxite IX has a lower ratio length/width, and the ovipositor is shorter than it is in C. sagartianum n. sp. Although the original description of C. guanche indicates that the ovipositor is broken in its terminal part, its preserved portion surpasses the length of the inner process of coxite IX by more than 3 times its own length (Mendes, 1993), and in C. sagartianum n. sp., the intact and wellpreserved ovipositor surpasses the inner process by only 1.5 times its length.

Ctenolepisma africanellum (described as C. africanella by Wygodzinsky) is clearly different from C. sagartianum n. sp. as follows: adults of C. africanellum are longer (up to 9.5 mm), while the longest specimens of C. sagartianum n. sp. are 6.7 mm long; C. africanellum has 5 prosternal combs and 4‒5 macrosetae in the submedian urosternal combs, whereas C. sagartianum n. sp. has 2‒3 prosternal combs and 6‒9 macrosetae in the submedian urosternal combs; coxites IX have a greater length/width ratio in C. africanellum , as shown in Figs. 356 and 358 in the original description (in females, about 1.5 and only 1.1 in C. sagartianum n. sp.); the ovipositor of C. africanellum is longer, clearly surpassing the apex of styli (not surpassing in C. sagartianum n. sp.) and the South African species has more divisions (45, opposed to 32‒33 in the new species).

Because of geographic proximity and similarity of characteristics, C. kervillei deserves a more detailed comparison with C. sagartianum n. sp. We were not able to fully compare C. sagartianum n. sp. with the original and supplementary descriptions of C. kervillei (Silvestri 1911, 1926). By current standards these descriptions are inadequate and lack many of the important characteristics used now for taxonomy of Ctenolepisma , such as the position of the trichobothrial areas, the number of macrosetae of the combs, and the shape of the thoracic sternites. Even though the description of C. kervillei needs updating, we think the characters given above are sufficient to conclude that the material identified here is a new species and does not fit with Silvestri’s species. In addition to Silvestri’s description we have used the comments given by Irish (1991) for C. kervillei specimens identified from Oman in our study of Ctenolepisma sagartianum n. sp.

One point of contention is the number of styli. Ctenolepisma kervillei was described as bearing only one pair of styli. The original description (Silvestri 1911), supplemented later (Silvestri 1926), was based on specimens from Syria. Nevertheless, Irish (1991) stated that specimens from Oman bearing two pairs of styli were conspecific with C. kervillei , taking their chaetotaxy into account. This discrepancy in stylus number was attributed to the fact that the type material of C. kervillei Irish examined was composed of juvenile specimens (“not quite mature”, according Irish). We doubt that the specimens from Oman are actually conspecific with Silvestri’s specimens, but regardless of this issue (which would require the examination of type and Oman material), there is a significant size difference. The biggest specimen of C. sagartianum n. sp. is 6.7 mm long, and the second pair of styli is developed when the insects have reached approximately 6 mm. However, Silvestri’s specimens with one pair of styli were longer than adult C. sagartianum n. sp. with two pairs of styli. Specimens from Syria were about 8 mm. Therefore, if C. kervillei develops a second pair of styli, either this development happens when specimens are longer than 8 mm, or perhaps never happens, if the population from Oman correspond to a different species. The specimens from Iran correspond to a taxon of a smaller size since 6-mm specimens with two pairs of styli can be considered adults.

Other characters given in Silvestri’s descriptive notes and drawings of C. kervillei that allow the detection of differences with C. sagartianum n. sp. can be discussed. The ratio length/width of the last article of the maxillary palp/length of the penultimate article is clearly greater than 1 in the C. kervillei drawing by Silvestri (1911), but in C. sagartianum n. sp. this ratio is about 1. The number of macrosetae of the combs of urotergite X is apparently 8 or more in C. kervillei , rather than 6 as in C. sagartianum n. sp. The ratio length/width of the inner process of the coxite IX in the male is greater than 1 in C. kervillei , while in C. sagartianum n. sp. this ratio is 1. Silvestri’s description indicated that the inner process of the coxite IX was “quam stilus parus magis quam dimidium breviore”, i.e., slightly shorter than half the length of the stylus. The examination of the drawings of Silvestri given in his work of 1926 allows to state that the styli are about 2.2 times longer than the inner process of the coxite IX, but in our specimens, the styli are more than 3 times longer than coxite IX, which are clearly different proportions. If the characters of the specimens studied by Silvestri can be interpreted as juvenile specimens, the conclusion is the same as given above: the specimens studied here from Iran are smaller, but adults. Finally, in the original description of C. kervillei , nothing is said about the chaetotaxy of the prosternum. However, Irish (1991), upon examination of the type material and additional material from Oman, stated that this species possessed 4 pairs of combs of macrosetae. Since C. sagartianum n. sp. has only 2‒3 irregular combs of macrosetae on the prosternum, it does not fit the specimens studied by Irish. This difference further confirms that they are not conspecific with the authentic C. kervillei , nor with the specimens from Oman.

Ctenolepisma kervillei has been reported from Iran, but the record is a mistake. Silvestri (1923) mentioned that two young specimens were collected at Jebel Hamrin, by a Capt. Evans in 1918. Jebel Hamrin is a mountain in northeastern Iraq, so C. kervillei still has not been reported for Iran, although the mentioned mountain is close to the Iranian border and C. kervillei may occur on western Iran (another possibility is that Silvestri erroneously associated those specimens to C. kervillei and they were actually C. sagartianum n. sp.).

Figures

FIGURE 10. Ctenolepisma sagartianum n. sp., Photomicrograph of the scales of the pronotum, holotype. Scale: 0.1 mm.

FIGURES 11 ‒ 16. Ctenolepisma sagartianum n. sp. Holotype. 11. Maxillary palp. 12. Labial palp, showing the position of the papillae of the apical article. 13. Prosternum. 14. Mesosternum. 15. Metasternum. 16. Apical part of the metasternum. Scales: 0.1 mm.

FIGURES 17 ‒ 20. Ctenolepisma sagartianum n. sp. 17. Hind tibia of the holotype showing the arrangement of macrosetae. 18. Urotergite X of the holotype. 19. Coxite IX and stylus of the holotype. 20. Coxite IX, stylus and ovipositor of a female paratype. Scales: 0.1 mm.