Oryctopterus varuna, Hiremath & Prathapan, 2021

Hiremath, S. R. & Prathapan, K. D., 2021, Two new species of the genus Oryctopterus (Orthoptera: Stenopelmatidae: Oryctopinae) from India, with some notes on biology, European Journal of Taxonomy 748 (1), pp. 108-137 : 111-128

Oryctopterus varuna sp. nov.

urn:lsid:zoobank.org:act:9E74ACC6-86D2-4A93-812A-5997835415D3

Figs 1–39 , 49–52 , 70

Diagnosis

Oryctopterus varuna sp. nov. can be differentiated from Ot. lagenipes ( Fig. 48 ) from Sri Lanka, by the following characters: (1) clypeus weakly narrowed ventrally in Ot. varuna sp. nov., more strongly narrowed ventrally in Ot. lagenipes , (2) first foretarsomere about 1.4 times as long as the rest combined in Ot. varuna sp. nov., 2.4 times as long as the rest combined in Ot. lagenipes , (3) hindwings fully developed in Ot. lagenipes ( Fig. 48 ) (much reduced in Ot. varuna sp. nov.: Figs 1–2 , 10–12 ). Oryctopterus varuna sp. nov. can be differentiated from Ot. yeshwanthi sp. nov. based on the structure of the mandible, pronotum and female genitalia, as mentioned under the latter species.

Etymology

The new species is named after Varuna, the god of rains in Indian mythology. The name is a noun in apposition. This cricket was observed coming out to open areas such as campus roads following rains, hence the name. In the regional dialect, Ot. varuna sp. nov. is called ‘ Mannunni ’, meaning ‘child of soil’. Also nicknamed ‘ Thanni-Pillai ’, meaning ‘baby of water’, alluding to its emergence following rains.

Type material

Holotype INDIA • ♂; Kerala, College of Agriculture, Vellayani ; 18 Mar. 2021; Kumar A. leg.; “HOLOTYPE; Oryctopterus varuna sp. nov.; des. Hiremath & Prathapan, 2021”; NBAIR.

Paratypes INDIA • 1 ♀ *; same collection data as for holotype; 3 Sep. 2019; S.R. Hiremath leg.; NBAIR • 1 ♀; Kerala, Vellayani; 10 Jul. 2007; K.D. Prathapan leg.; NBAIR • 1 ♀; same collection data as for preceding; 23 Jul. 2015; Ashwathi leg.; NBAIR • 1 ♀; same collection data as for holotype; 7 Jun. 2018; Mithra Mohan leg.; NBAIR • 3 ♀♀; same collection data as for holotype; Student leg.; NBAIR • 1 ♀; same collection data as for holotype; 20 Aug. 2019; Student leg.; NBAIR • 1 ♀ *; same collection data as for holotype; 8 Sep. 2019; S.R. Hiremath leg.; NBAIR • 1 ♀; same collection data as for holotype; 23 Oct. 2019; S.R. Hiremath leg.; NBAIR • 1 ♀; same collection data as for holotype; 3 Mar. 2020; Amritha Hari leg.; NBAIR • 1 ♀; same collection data as for holotype; 21 Mar. 2020; S.R. Hiremath leg.; NBAIR • 1 ♀; same collection data as for holotype; 10 Jan. 2021; Pradeep D leg.; NBAIR • 1 ♂; same collection data as for holotype; 21 Mar. 2021; Pradeep D leg.; NBAIR • 1 ♀; same collection data as for holotype; 6 Nov. 2019; Gouripriya leg.; UASB • 1 ♀; same collection data as for holotype; 10 Jan. 2020; S.R. Hiremath leg.; UASB. (* Presence of mature eggs confirmed through dissection) .

Other material

INDIA • 1 ♂; same collection data as for holotype; 2019; Student collection leg. (lost after the specimen was studied and illustrated: Fig. 10 ) .

Description

Male ( Figs 1–17 )

COLORATION. General color chestnut brown; abdominal tergites, tegmina darker than head, thorax and sternites. Vertex and frons demarcated by M-shaped dark marking; a U-shaped dark stripe extends vertically over vertex ( Figs 5–6 ), a single vertical stripe arises from each eye and a third pair of vertical stripes arise from the gena. Some of this stripes may be indistinct. Clypeus straw brown in distal half, concolorous with frons in proximal half. Labrum concolorous with frons. Tegmina chestnut brown. Abdominal tergites dark brown.

HEAD. Vertex strongly convex. Distance between eyes 1.41 times distance between antennal sockets. M-shaped dark marking demarcating vertex, frons depressed. Frons moderately convex between antennal sockets, gradually turning flat and gently depressed ventrally; without wrinkles, except few beneath eye. Eyes with mesal margin concave near antennal socket, lateral margin strongly rounded. Antenna extends well beyond apex of tegmina. Clypeus more or less as long as labrum, trapezoidal, narrowed ventrally, a little wider than long, with a vertical sulcus originating from middle of anterior margin, indistinct in proximal half. Mandibles exceed length of labrum.

THORAX. Pronotum 1.76 times wider than long, anteriorly 0.95 times wider than posteriorly ( Fig. 6 ). Lateral margin evenly curved; anterolateral margin convex, forming somewhat obtuse angle with anterior margin. Posterior margin apparently bisinuate. Pronotal anteapical transverse impression merged with anterolateral depressions on either side. Oblique sulcus originating from postero-lateral corner of pronotum shallow. Tegmina not covering supragenital plate and 1–5 preceding tergites. Costa 3-branched, subcosta (Sc) unbranched, reaches between apical ¼ and apex; RA 3 or 4-branched, RS + M 1 unbranched or 2-branched, 2 MA 1 unbranched or 2-branched ( Figs 10–12 ). Hindwings much shorter than tegmina ( Figs 10–12 ). Prosternite wider than long, converging posteriorly, posterior margin emarginate medially, with two pairs of ventral cervical sclerites; lateral cervical sclerites acutely narrowed distally, oblique; prosternite distally with raised setose portion medially. Metathoracic basisternum with posterior margin emarginate medially.

HIND LEGS. Coxa depressed ventrally. Dorsolateral and dorsomesal margins of metatibia with a row of 3–6 sharp denticles.

ABDOMEN ( Figs 7–9 ). Supragenital plate triangular with inverted Y-shaped sulcus medially, apex rounded ( Figs 1–2 , 7 ). Subgenital plate with convex posterior margin ( Figs 14–15 ). Subgenital plate constricted in distal third, apex rounded; with a pair of long apodemes proximally ( Figs 14–15 ).

GENITALIA ( Figs 13–14 ). Genital hooks long, pointed, gently curved, with 6 setae on apex.

MEASUREMENTS (mm) (n = 3). Body length: 27.50–37.68, head width: 7.55–7.89, pronotal length: 4.42– 4.73, pronotal width: 8.08–8.30, forefemur: 8.94–9.11, foretibia: 9.88–10.98, foretarsi: I. 3.39–4.31, II. 0.54–1.46, III. 1.39–1.46, IV. 1.08–1.16, midfemur: 7.76–8.11, midtibia: 8.30–9.01, midtarsi: I. 1.85– 3.08, II. 1.08–1.16, III. 1.16–1.39, IV. 1.31–2.31, hindfemur: 13.17–13.35, hindtibia: 13.47–14.81, hindtarsi: I. 2.46–4.54, II. 1.46–1.62, III. 1.54–1.85, IV. 1.54–2.70. Proportionate length of forefemur: foretibia: foretarsi: midfemur: midtibia: midtarsi: hindfemur: hindtibia: hindtarsi as follows: 1.00: 1.09– 1.23: 0.72–0.92: 0.87–0.89: 0.92–0.98: 0.59–0.89: 1.46–1.48: 1.49–1.66: 0.77–1.19. Proportionate length of tarsomeres I–IV: foreleg – 1.00: 0.16–0.34: 0.32–0.41: 0.25–0.34; midleg – 1.00: 0.38–0.58: 0.45–0.66: 0.70–0.75; hindleg – 1.00: 0.36–0.59: 0.39–0.63: 0.59–0.63.

Female ( Figs 18–39 , 49–52 )

COLORATION. General color chestnut brown; abdomen darker than head and thorax; legs lighter than thorax. Vertex and frons demarcated by M-shaped dark marking; a U-shaped dark stripe extends vertically over vertex ( Fig. 21 ), a single vertical stripe arise from each eye and a third pair of vertical stripes arise from the gena. The stripes may be obliterated in some specimens. Clypeus straw brown, distinctly lighter than frons. Labrum proximally concolorous with clypeus, gradually turning darker towards distal area. Thoracic sternites lighter than tergites.

HEAD. Vertex strongly convex. Distance between eyes 1.27–1.40 times distance between antennal sockets. Frons moderately convex between antennal sockets, gradually turning flat to depressed ventrally; minutely wrinkled in ventral half. Eyes with mesal margin concave near antennal socket, lateral margin strongly rounded. Antenna just crosses anteapical sulcus of pronotum. Clypeus a little shorter than labrum, trapezoidal, narrowed ventrally, a little over twice wider than long, with a vertical sulcus originating from middle of anterior margin, depressed on either side of vertical sulcus. Mandibles exceed length of labrum.

THORAX. Pronotum 1.67–1.79 times wider than long, anteriorly 1.12–1.26 times wider than posteriorly ( Fig. 22 ). Lateral margin evenly curved; anterolateral margin convex, forming somewhat obtuse angle with anterior margin. Posterior margin concave medially. Pronotal anteapical transverse impression merged with anterolateral depressions on either side. Oblique sulcus originating from postero-lateral corner of pronotum not discernible. Prosternite wider than long, converging posteriorly, posterior margin emarginate medially, with two pairs of ventral cervical sclerites; lateral cervical sclerites acutely narrowed distally, oblique; prosternite distally with raised setose portion medially. Metathoracic basisternum with posterior margin emarginate medially.

HIND LEGS. Coxa depressed ventrally. Dorsolateral and dorsomesal margins of metatibia with a row of five small denticles, proximal one or two hardly noticeable.

ABDOMEN ( Figs 23–28 ). Supragenital plate almost semicircular ( Figs 23 , 26 , 29–31 ). Subgenital plate with arcuate posterior margin ( Figs 25 , 27 ).

GENITALIA ( Figs 32–36 ). Ovipositor with dorsal valve broader and slightly longer than ventral one. Base of ventral valve with two pairs of obliquely placed rod shaped sclerites, inner one shorter than outer. Vagina longer than dorsal valve, conical with lateral sides each bearing an elongate, rectangular, unsclerotized vaginal plate at middle. Spermathecal duct elongate, narrow tube with spindle shaped bulb near middle, entering vagina dorsally at middle. Median oviduct merged with ventral wall of vagina. Spermatheca spherical, with smooth integument. Spermathecal gland tubular, narrower and distinctly longer than spermathecal duct. Spermathecal gland with two spindle shaped bulbs near basal third and slightly elongate, spindle shaped bulb at apex ( Fig. 36 ). Sternite VIII transverse with apical margin broadly rounded and weakly projected at middle, integument concentrated with elongate red-brown setae ( Fig. 34 ).

MEASUREMENTS (mm) (n = 4). Body length: 26.02–37.64, head width: 8.62–12.57, pronotal length: 5.13–7.29, pronotal width: 8.57–13.05, forefemur: 7.71–10.13, foretibia: 9.95–13.77, foretarsi: I. 4.42– 6.05, II. 1.01–1.78, III. 0.86–1.49, IV. 0.67–1.01, midfemur: 6.63–9.23, midtibia: 7.44–11.24, midtarsi: I. 2.59–3.60, II. 0.82–1.34, III. 0.96–1.25, IV. 1.63–2.30, hindfemur: 10.23–14.20, hindtibia: 9.53–13.62, hindtarsi: I. 3.17–5.38, II. 1.20–1.68, III. 1.20–1.68, IV. 1.92–2.88. Proportionate length of forefemur: foretibia: foretarsi: midfemur: midtibia: midtarsi: hindfemur: hindtibia: hindtarsi as follows: 1.00: 1.16–1.36: 0.89–1.09: 0.70–0.91: 0.94–1.11: 0.76–0.84: 1.27–1.40: 1.15–1.34: 0.97–1.05. Proportionate length of tarsomeres I–IV: foreleg – 1.00: 0.23–0.29: 0.19–0.25: 0.15–0.17; midleg – 1.00: 0.32–0.39: 0.29–0.37: 0.47–0.68; hindleg – 1.00: 0.27–0.45: 0.27–0.41: 0.43–0.65.

Sexual dimorphism

Male (27.50–37.68 mm) apparently subequal in length to the female (26.02–37.64 mm), with fully developed wings, female apterous and stouter. Claws of forelegs well developed in male, absent in female. Spines on metatibia well developed and sharp in male, much reduced or hardly discernible in the female.

Remarks

Oryctopterus varuna sp. nov. and Ot. lagenipes were geographically isolated multiple times in the Quarternary and most recently during the separation of Sri Lanka from south India, around 7500 years ago with the Holocene rises in sea level ( Gunatilaka 2000). Poorly developed hind wings indicate that Ot. varuna sp. nov. could be flightless, despite being alate. Wing venation varies considerably, in the branching pattern, shape of veins and cross veins ( Figs 10–12 ). Béthoux (2012) showed that in king crickets, raspy crickets and weta, wing venation vary greatly within species and several species delimited based on wing venation are synonyms. Ross (2012), who studied cockroaches, proved that forewings of a cockroach species vary considerably; even the left and right wings on the same specimen are slightly different. According to Ross (2012), since forewings in cockroaches are not used for active flight, the positions of the veins, which are important for the aerodynamics and flexing of the wings, vary greatly. The intraspecific variation in the wing venation in Oryctopterus , could be the outcome of a flightless, subterranean mode of life.

Oryctopterus varuna sp. nov. is only known from the Vellayani campus of the Kerala Agricultural University (8°25′46.3″ N, 76°59′07.8″ E, 39 m elevation). Description of this new species underscores the importance of biodiversity conservation in periurban areas, as reckless development is taking its toll on all life forms in every imaginable habitat, throughout India and elsewhere.

Notes on biology

Female reproductive system

Ovaries were paired and each ovary ( Fig. 37 ) consists of more than 10 panoistic ovarioles, each ovariole containing about six eggs ( Fig. 38 ). A total of about 175– 200 eggs were present inside the ovaries of an individual. Mature eggs are lemon-shaped ( Fig. 39 ). Fully developed eggs in the ovary indicate that the dissected as well as the other examined specimens, which are morphologically identical, are probably all adults.

Habitat

Vellayani campus of the Kerala Agricultural University is the sole known habitat of the new species. The total area of the campus is about 2.52 km 2. This is a highly populated residential area and the open lands are under cultivation with various agricultural crops. Chemical fertilizers and pesticides are used to raise the crops. The campus has a network of roads connecting academic and residential buildings and other facilities. The soil type is red loam and the average annual rainfall is 1577 mm.

Seasonality

Most females were seen walking on the open campus roads during or after a downpour, both during day and night. One individual was caught around midday on 8 September 2019, when it was bright and sunny. Emergence of females of Ot. varuna sp. nov. coincides with the south-west monsoon rains during June to September. However, males are extremely rare and two individuals were collected following summer rains during the peak summer of March 2021.

Food habits as indicated by the gut contents ( Figs 40–47 )

Examination of the gut contents of three of the specimens revealed the presence of mandibles of mandibulate soldiers ( Figs 40–41 ) and workers ( Fig. 42 ) of the termite Odontotermes sp. (Blattaria, Termitidae ); and the body parts, including head ( Fig. 43 ), thorax ( Figs 44–45 ), and abdomen of ants (probably Pheidole sp. , Hymenoptera , Formicidae ). Interestingly, a piece of the stem of a plant (0.58 mm × 0.43 mm) ( Fig. 46 ) and sand particles (0.24–0.62 mm diameter) ( Fig. 47 ) were also observed inside the gut.

Behavior

The new species is a ‘heel-walker’ ( Fig. 49 , Supp. file 3). They walk on the distal tip of tibiae with the foretarsi always held raised, while the mid- and hind tarsi are in close proximity to the ground, yet not touching it while walking. However, when not moving, all the tarsi may touch the ground. While walking, the long maxillary palpi are held forward and constantly touch the objects in the foreground in tandem. South African Jerusalem Crickets are known to hop and climb vegetation ( Weissman & Bazelet 2013) while some of the New World species exhibit drumming (abdomen striking against the substrate) ( Weissman 2001a). However, no such behaviors were observed in O. varuna sp. nov. When a female was held above the ground level on a flat substrate, it rather tumbled down instead of hopping. It also failed to climb up sticks on which it was placed. A male was observed flapping wings and performing short jumps of about 0.3 m.

Defense

Oryctopterus varuna sp. nov. displayed intricate defensive postures when intimidated. Confronted from the front, the cricket sprang into a pouncing posture, raised its forelegs and waved in mid-air, the mandibles opened widely, as if ready to bite ( Fig. 50 , Supp. file 1). When approached from the anterolateral side, it raised the front leg on that side to defend. However, when the animal was poked on the thorax, in addition to the forelegs, the abdomen also was raised, to startle the attacker ( Fig. 51 ). When an individual is pinned down with the index finger firmly pressed on the thorax, the whole body was flexed and all legs were raised and started kicking to fend off the assailant. They inflicted painful bites when handled. Weissman (2001a) reported that New World Stenopelmatine, when confronted, frequently flip on their back, with mandibles agape, or can rear up.

Burrowing

Burrowing was observed by releasing an adult female into a 23.50 cm high, 21.50 cm wide polypropylene tub filled with loose soil up to ⅔ the height of the tub. Mainly head and legs are used in burrowing. To begin with, the forelegs were firmly held against the ground to anchor the body, then the head was bent down, moving forward and backward to dig up the soil, with the mandibles acting like a shovel ( Fig. 52 , Supp. file 2). The dug-up soil was then pushed backwards and sideways with hindlegs and midlegs respectively. In the laboratory, it made a burrow that was vertical initially but turned oblique, then horizontal and nearly parallel to the surface. Observed behavior suggests that the Oryctopinae are subterranean, inhabiting underground burrows.

Figures

Figs 1–4. Oryctopterus varuna sp. nov., ♂. 1. Holotype (NBAIR), dorsal habitus. 2–4. Paratypes (NBAIR). 2. Dorsal habitus. 3. Ventral habitus. 4. Lateral view. Scale bars = 10 mm.

Figs 5–9. Oryctopterus varuna sp. nov. Paratype, ♂ (NBAIR). 5. Head, frontal view. 6. Head and pronotum, dorsal view. 7–9. Apex of abdomen. 7. Dorsal view. 8. Ventral view. 9. Lateral view.Scale bars = 5 mm.

Figs 10–12. Oryctopterus varuna sp. nov., ♂. 10. Lost specimen. 11. Holotype (NBAIR). 12. Paratype (NBAIR). Abbreviations: see Material and methods. Scale bars = 5 mm.

Figs 13–17. Oryctopterus varuna sp. nov. Paratype, ♂ (NBAIR). 13. Supragenital plate and cerci. 14. Subgenital plate, dorsal view. 15. Subgenital plate, ventral view. 16. Genital hook and associated structures, ventral view. 17. Genital hook. Scale bars = 1 mm.

Figs 18–21. Oryctopterus varuna sp. nov. Paratype, ♀ (NBAIR). 18. Dorsal habitus. 19. Ventral habitus. 20. Lateral habitus. 20. Head, frontal view. Scale bars = 5 mm.

Figs 22–25. Oryctopterus varuna sp. nov. Paratype, ♀ (NBAIR). 22. Head and pronotum, dorsal view. 23–25. Apex of abdomen in preserved specimen. 23. Dorsal view. 24. Lateral view. 25. Ventral view. Scale bars = 5 mm.

Figs 26–28. Oryctopterus varuna sp. nov. Apex of male abdomen in freshly killed specimen (NBAIR). 26. Dorsal view. 27. Ventral view. 28. Lateral view. Scale bars: 26–27 = 5 mm; 28 = 1 mm.

Figs 29–31. Oryctopterus varuna sp. nov. Paratype, ♀ (NBAIR). 29. Supragenital plate and cerci, dorsal view (macerated specimen, through transmitted light). 30. Supragenital plate, cerci and alimentary canal, dorsal view (macerated specimen). 31. Supragenital plate, cerci and alimentary canal, ventral view (macerated specimen). Scale bars = 1 mm.

Figs 32–36.Oryctopterus varuna sp. nov., female genitalia. Paratype (NBAIR).32. Dorsal view.33. Dorsal view (valves separated). 34. Ventral view. 35. Ventral view (without sternite VIII). 36. Spermatheca Abbreviations: see Material and methods. Scale bars = 1 mm.

Figs 37–39. Ovary, ovarioles and egg of Oryctopterus varuna sp. nov. Paratype, ♀ (NBAIR). 37. Ovary. 38. Ovariole. 39. Egg. Scale bars: 37–38 = 1 mm; 39 = 0.1 mm.

Figs 48–52.Oryctopterus species. 48. Oryctopterus lagenipes(Karny, 1935), allotype, ♂, from Colombo, Sri Lanka (Karny 1937: pl. 7 fig. 2; available from Orthoptera species file). 49–52. Oryctopterus varuna sp. nov. 49. Walking posture. 50. Defending a frontal attack. 51. Abdomen and fore-legs raised when poked on thorax. 52. Initiation of digging. Images not to scale.

Fig. 70. Distribution of Oryctopinae Kevan, 1986 species.

Figs 40–47. Gut contents of Oryctopterus varuna sp. nov. 40–41. Mandibles of Odontotermes sp. soldier. 42. Mandible of Odontotermes sp. worker.43. Head of Pheidole sp.44–45. Thorax of Pheidole sp. dorsal and lateral views. 46. Piece of stem. 47. Pebbles. Scale bars: 40–42, 46–47 = 0.1 mm; 43–45 = 0.5 mm.