Acrotelsella jhargramensis, Hazra & Jana & Smith, 2023

Hazra, Ashis Kumar, Jana, Debanjan & Smith, Graeme, 2023, A new species of the genus Acrotelsella (Zygentoma: Lepismatidae) from Jhargram West Bengal, India, Zootaxa 5227 (5), pp. 594-600 : 594-599

Acrotelsella jhargramensis sp. n.

( Figures 1–18, Table 1)

Type material. Holotype male under the bark of a Sal tree ( Shorea robusta ), Bandarbhola, Jhargram, West Bengal, India [22°25′38″ N, 87°15′37″ E, elevation 82 m], 21.xi.2019, 1 male, coll. Dr. A. K. Hazra & D. Jana, Registration number 3144/H14, Zoological Survey of India, Kolkata . Paratype male, same date and locality as holotype, Registration number 3145/H14, Zoological Survey of India, Kolkata .

Etymology. The species is named after the type locality, the district Jhargram, West Bengal, India.

Diagnosis. Apical article of labial palps with high number of sensory papillae (10‒12); labrum with macrosetae not arranged in bushes; trichobothria lacking from the most posterior comb of the mesonotum; prosternum with 4+4 bristle combs of macrosetae, mesosternum with 2+2 bristle combs of macrosetae and metasternum with 1+1 bristle combs of macrosetae. Urotergite X acutely triangular (44°) with sharp and pointed apex; two pairs of abdominal styli.

Description. Holotype male body length 12.4 mm in life, mottled brown with dark annulated antennae and caudal appendages ( Fig. 1). Base colour (in alcohol) dorsally brownish yellow with a covering of light brown scales, ventrally whitish yellow. Shape of the body elongate, more or less parallel-sided, dorsoventrally compressed anteriorly, sub-cylindrical posteriorly; thorax slightly wider than abdomen ( Fig. 2 ). Faintly brownish but distinct pigment on the segments of the maxillary palp. Antennae and caudal appendages with alternate dark and light bands of brown pigmentation. Antennal length 16.9 mm, longer than body and surpassing the body by 1.3 times when directed backwards. Near base, flagellomeres with one annulus; ninth interval composed of two annuli; most distal part of the antennae with eight annuli in each flagellomere; fifth annulus in each interval a dark ring. Oval scales present on both the scape and pedicel, basiconic sensilla present on apical flagellomeres.

Head semi-circular in outline anteriorly; frons bearing two very conspicuous tufts of stout cephalic setae, pectinate and radially arranged. Numerous bifid and pectinate macrosetae present on both clypeus and labrum, those of the clypeus grouped in two tufts composed of 30‒32 macrosetae each and those on the labrum scattered over the outer third ( Fig. 3 ). Eyes relatively small, located well behind the antennae. Head wider (1.42 mm) than long (0.98 mm).

Maxillary palp ( Fig. 4 ) five-segmented; terminal segment (0.45 mm) longer than penultimate segment (0.34 mm). Apical segment of labial palp ( Figs. 5, 6 ) bearing ten horizontal sensory papillae on left labial palp and twelve horizontal sensory papillae on right labial palp, arranged in single rows; apical segment about 2.4× wider at the apex than at the base and 1.5× wider than long.

Medial part of the pronotal collar ( Fig. 7 ) composed of two rows of macrosetae, lateral regions with a single row of smooth macrosetae. Lateral margins of pronotum with 7+7 combs composed of 1−2 macrosetae each. Two trichobothrial areas on each side, associated with the inner end of the last comb (N) and between the two macrochaetae of N-3. Lateral margins of mesonotum ( Fig. 8 ) with 12+11 combs each consisting of 1−3 macrosetae, including one trichobothrium between the macrochaeta and the margin of N-2; no macrochaetae associated with the trichobothrium of the most posterior lateral combs of the mesonotum. Lateral margins of metanotum ( Fig. 9 ) with 10+10 combs composed of 1−3 macrosetae, including two trichobothrial areas, the trichobothrium located on the inner side of comb N and between the macrochaeta and the margin of comb N−1. Hind borders of pro, meso and metanota with 1+1 submedial bristle combs composed of five macrosetae each, the two pronotal combs separated by about 0.4× the width of the pronotum.

Prosternum ( Fig. 10 ) 1.4 mm long, length/width ratio about 0.9, subtriangular, posteriorly rounded; posteriorly with 4+4 bristle combs each composed of 2−5 macrosetae. Mesosternum ( Fig. 11 ) 1.7 mm long, length/width ratio about 0.9, rounded-triangular in shape, with 2+2 posterior bristle combs each composed of four macrosetae. Metasternum 1.4 mm long, length/width ratio about 0.7; posterior margin broadly rounded with 1+1 bristle combs, each composed of seven macrosetae ( Fig 12 ); distance between metasternal combs 5.4× the width of a comb.

Legs stout; femora moderate in size; tibiae and tarsi moderately elongate; pretarsi with slightly curved claws ( Fig. 13 ). Scales present on coxae, femora, tibia and first tarsomere ( Fig. 14 ). Length/width ratio of protibia about 2.5× longer than wide; protibia with two macrosetae inserted on dorsal margin, six macrosetae on ventral margin. Lengths of fore tarsomeres I‒IV 0.41, 0.13, 0.18 and 0.2 mm, respectively. Mesotibia 2.9× longer than wide, with two dorsal and five ventral macrosetae. Lengths of middle tarsomeres I‒IV 0.51, 0.16, 0.19 and 0.22 mm, respectively. Metatibia about 3.3× longer than wide, with two dorsal and four ventral macrosetae. Lengths of hind tarsomeres 0.71, 0.16, 0.21 and 0.26 mm, respectively.

Urotergite I with 1+1 bristle-combs, each composed of five macrosetae; urotergites II−VII with 3+3 bristlecombs, each composed of 4−10 macrosetae; urotergite VIII with 2+2 bristle-combs, each composed of 4−12 macrosetae. Urotergite IX without bristle combs. The number of macrosetae per bristle comb on urotergites given in Table 1. Urotergite X ( Fig. 15 ) triangular with sharply pointed apex; length 0.14 mm, length/width ratio about 1.2, with 4+4 bristle-combs of 2−4 macrosetae each.

Urosternites I and II without setae, III−VIII with 1+1 lateral bristle-combs, each composed of 13−15 macrosetae. Width of the bristle combs and the gap between them varying on each urosternite; ratio of the distance between the combs and the width of a comb ranges from 3.0 on urosternite VIII to 6.2 on urosternite IV ( Fig. 16 ).

Two pairs of styli present, inserted on segments VIII ( Fig. 17 ) and IX ( Fig.18 ), both covered with scales. Styli IX length 1.4× that of styli VIII. Posterior margin of coxite VIII between the combs almost straight. Inner process of coxite IX long, triangular and pointed at tip with the angle of the posterior point (44°), about 1.6× longer than wide at its base and 1.8× longer than the outer process. Penis shape typical for the subfamily; length 0.53 mm, length/width ratio 0.8.

Length of caudal filament up to 9.7 mm, that of cerci up to 9.9 mm. Most distal flagellomere of the caudal appendages with eight annuli, major macrochaetae restricted to the most distal annulus. Scales present on annuli 2, 4 and 6. Pigment absent from the most distal and most basal annuli of each flagellomere resulting in the banded appearance.

Distribution and habitat. The specimens belonging to this new species were found under the bark of Sal trees ( Shorea robusta ) of Bandarbhola at Jhargram, West Bengal, India. Red laterite is the predominant soil in the district, supporting undergrowth of various types of herbs and shrubs on the forest floor. The weather is extremely humid and tropical. There are large numbers of termite mounds present on the forest floor.

Figures

FIGURES 2‒6. Acrotelsella jhargramensis sp. n. Male. 2) Dorsal habitus. 3) Head chaetotaxy with clypeus and labrum. 4) Maxillary palp. 5) Labial palp (left half) with sensory papillae. 6) Labial palp (right half) with sensory papillae. Scales: Fig. 2, 10 mm; Figs. 3‒6, 0.1 mm.

FIGURES 7‒12. Acrotelsella jhargramensis sp. n. Male. 7) Pronotum. 8) Mesonotum. 9) Metanotum. 10) Prosternum. 11) Mesosternum. 12) Metasternum. Scales: 1 mm.

FIGURES 13‒18. Acrotelsella jhargramensis sp. n. Male. 13) Hind leg. 14) Different types of scales present in the hindlegs. 15) Tergite X. 16) Urosternite IV. 17) Sternite VIII with styli and scales. 18) Coxite IX with styli and scales. Scales: Figs. 13, 15‒18, 1 mm; Fig. 14, 0.01 mm.