Ctenolepisma calvum ( Ritter, 1910 )

Ctenolepisma calvum ( Ritter, 1910)

( Figs 4-11 View FIG View FIG View FIG View FIG View FIG View FIG View FIG View FIG )

Peliolepisma calva Ritter, 1910: 380 .

Ctenolepisma calvum – Paclt 1967: 39. Peliolepisma calvum – Paclt 1979: 223.

MATERIAL STUDIED. — Neotype. India • 1 ♀; Kerala, Thrissur District, Valarkkavu , bookcase in a house; 22.IX.2022; S. Raphel leg., specimen in alcohol; ZSI / WGRC, I.R.-INV.26922 .

OTHER MATERIAL STUDIED. — India • 1 ♀; same locality as neotype; 12.IV.2023; specimen in alcohol; ZSI / WGRC, I.R.-INV.26923 .

DIAGNOSIS. — Body length up to 9.75 mm. Macrosetae plumose. Epidermic pigment whitish to light yellowish. Dorsal scales transparent, light yellowish, heterogeneous in shape and in the spacing of their ribs, but more uniform than those of C. rothschildi Silvestri, 1907 . Appendages lacking scales except for coxae and femora; coxal scales similar to those covering the body and femoral scales present only on the inner side, their shape subtriangular with truncated or bifid apical margin. Antennae shorter than body length. Cephalic chaetotaxy typical of Ctenolepisma . Last article of labial palp with five sensory papillae arranged in a single row. Setal collar of pronotum with two rows of macrosetae on its median part. Lateral margins of pronotum and mesonotum bearing 8-10 pairs of lateral bristle-combs; metanotum with 5-7 lateral combs on each side. Posterior margins of thoracic nota with 1 + 1 posterior small combs of 2-3 macrosetae each. Anterior trichobothrial areas of pronotum associated to the N-4 or N-5 lateral combs; those of mesonotum and metanotum associated to the penultimate (N-1) comb. Posterior trichobothria inserted on the last lateral comb of each notum. All thoracic sterna with 1 + 1 antedistal bristle-combs bearing 5-10 macrosetae, frequently arranged in two irregular rows. Abdominal tergite I with 1 + 1 infralateral combs of two macrosetae. Urotergites II-V with 3 + 3 combs, urotergites VI-VIII with 2 + 2 combs and urotergite IX glabrous; infralateral combs consisting of 2-5 macrosetae; remaining dorsal combs of abdomen with 2-3 macrosetae. Urotergite X trapezoidal, short and with a slightly concave posterior margin. Urosternites I and II lacking setae; urosternites III-VIII with 1 + 1 lateral combs of 10-13 macrosetae.Two pairs of styli inserted on abdominal segments VIII and IX. Inner process of coxite IX about 1-1.6 times longer than wide at its base and about 2-2.4 times longer than the outer process. Ovipositor moderately long, with about 30-33 divisions; its apex surpassing the tip of styli IX by about 0.5 times the latter’s length. Maximum length preserved of caudal filaments up to 5.25 mm. Male unknown. Ctenolepisma calvum is close to C. rothschildi , but the dorsal scales are more uniform (big pauciradiate scales occurring in C. rothschildi are absent), the colour of scales and epidermic pigment is lighter (in C. rothschildi the colour pattern seems to be variable but the pigment is always darker), the number of macrosetae on sternites is greater (in C. rothschildi , the combs of thoracic sternites have less than 8 macrosetae, not arranged in two rows, and the combs of abdominal sternites have less than 10 macrosetae) and the ovipositor is shorter (in C. rothschildi , its apex exceeds the tip of the last pair of styli by 1-2 times their length).

REDESCRIPTION

Male unknown. Body of female elongated, more or less parallel sided, slightly tapering towards the posterior end ( Fig. 4 View FIG ). Maximum body length: 9.75 mm, excluding terminal filaments. Macrosetae pectinate ( Figs 5 View FIG ; 6 View FIG ). Epidermic pigment whitish dorsally, with slightly grey pigmentation; under artificial light colour appearing light straw, covered with dull golden scales. Maximum length of cerci up to 4.5 mm and that of paracercus up to 5.25 mm.

Scales

Dorsal and ventral surface of the body covered with heterogeneous scales; based on shape, sometimes be oval, globular and sub-triangular; based on size, sometimes be large (more than 100 µm) and small (less than or equal to 30 µm). Based on rays, two types distinguished: one with 30-40 fine rays and the other with 10-16 widely spaced thicker rays. The three different shaped scales of both small and large sizes, with either wide spaced or narrow spaced rays ( Fig. 5 View FIG ). Appendages lacking scales except for coxae and femora; femoral scales are different in shape, elongated, with bifid apex ( Fig. 6 View FIG ).

Head

Head wider (maximum 1.1 mm) than long (maximum 0.70 mm). Setation similar to other species of the genus, with both clypeus and labrum having setal bushes of bifid and pectinate macrosetae ( Fig. 7 View FIG ). Antennae up to 6 mm long. Maxillary palp 5-segmented; apical article 4.2-6.5 times longer than wide and 0.74-1.00 times as long as the penultimate article. Four segmented labial palps, their apical article being slightly longer than wide (L/W: 1.1-1.2) with five sensory papillae arranged in single row ( Figs 7 View FIG ; 8A View FIG ).

Thorax

Thorax wider than abdomen. Maximum thorax width: 2.12 mm; maximum thorax length: 3.1mm. Pronotal collar with two rows of bristle combs in the centre and single row towards the anterolateral corner. Pronotum ( Figs 5 View FIG ; 8B View FIG ) with (8-9) + (8-10) bristle combs on lateral margins, each one with 2-5 macrosetae; posterior trichobothria of pronotum on inner side of the last lateral comb (N) and anterior trichobothria on inner side of N-4 or N-5 combs. Mesonotum ( Fig. 8C View FIG ) with (8-9) + (8-9) lateral combs of 2-3 macrosetae; posterior trichobothria on the inner side of the last lateral comb (N) and anterior on the outer side of the penultimate lateral comb (N-1). Metanotum ( Fig. 8D View FIG ) with (5-6) + (5-7) bristle combs of 1-3 macrosetae each on its lateral margins; arrangement of trichobothria similar to that of mesonotum. All nota with 1 + 1 posterior submarginal combs with 2-3 macrosetae.

Thoracic sterna as in Figure 9 View FIG . Prosternum and mesosternum longer than wide; ratio L/W of the prosternum: 1.16-1.20, and ratio L/W of the mesosternum: 1.20-1.26. Metasternum as long as wide or slightly shorter (ratio L/W:0.92-1.00). All thoracic sterna with one pair of oblique antedistal combs; those of prosternum and metasternum with 7-10 macrosetae, and those of mesosternum consisting of 5-8 macrosetae. In all sterna, macrosetae of the combs arranged in two irregular rows, and few submarginal setae also present between the comb and the margin.

Legs

Legs stout; femora shorter than tibiae and tarsi. Tarsi of hind legs moderately longer than that of other two legs. Protibiae 3.0-3.5 times longer than wide; mesotibiae 3.0-3.8 times longer than wide and about 1.14-1.19 times longer than the protibiae; metatibiae 3.6-5.2 times longer than wide and 1.5- 1.6 times longer than the protibiae.

In the tarsi of the first legs, tarsomere 1 (T1) 3.5-5.5 times longer than tarsomere 2 (T2), 3.7-4.8 times longer than tarsomere 3 (T3) and 3.2-5.6 times longer than tarsomere 4 (T4). In the mesotarsus, tarsomere 1 5.3-6.0 times longer than T2, 4.0-6.4 times longer than T3 and 4.6-4.8 times longer than T4. In the metatarsus, T1 5.30-6.65 times longer than T2, 6.5-9.0 times longer than T3 and 4.0-5.6 times longer than T4. Femur with subtriangular elongated bifid scales ( Fig. 6 View FIG ) on their inner side. Pretarsus with 3 claws, two lateral and one median.

Abdomen

Urotergite I with 1 + 1 infralateral combs of 2-3 macrosetae, urotergites II-V with 3 + 3 bristle combs, urotergites VI and VIII with 2 + 2 combs and urotergite IX bare. Urotergite X trapezoidal in shape ( Fig. 10 View FIG ), wider than long (in the neotype, length: 0.56 mm and base width: 1.4 mm), with 1 + 1 subapical bristle combs consisting of 2-3 macrosetae; scattered setae arranged as in Figure 10 View FIG . Urosternites I and II glabrous, urosternites III-VII with 1 + 1 lateral combs of 10-13 macrosetae. Number of macrosetae on abdominal bristle combs, see Table 3 View TABLE .

Two pairs of styli inserted on abdominal segments VIII and IX ( Fig. 11 View FIG ), apically with several spines. Styli IX longer than styli VIII; ratio of length of styli IX/ length of styli VIII: 1.06-2.08. Inner process of the coxite IX long, triangular and pointed at tip, about 1.00-1.66 times longer than wide at its base and 2.0-2.4 times longer than the outer process. Ovipositor with 30-33 divisions; 1.36-1.76 mm in length from base of urosternite VIII, surpassing the apex of the inner processes of coxites IX by 2-4 times its length.

REMARK

The status and whereabouts of the types of C. calvum are unknown. Ritter (1910) mentioned that the Sri Lankan specimens he studied were deposited in the k.k.k. Naturhistorisches Museum; we guess this is the Natural History Museum of Vienna ( Austria), but it seems that the specimens are lost or damaged (perhaps during the World War II). Querner et al. (2022) provided some descriptive details of this species but did not use the type of the species in spite of these authors working at this Austrian Museum. So we designed here a neotype to fix the taxonomy of the species, even though the specimen comes from Kerala (S. India) and not Sri Lanka.