Omorgus (Omorgus) khandesh Strümpher & Kalawate, new, 2023

Strümpher, Werner P. & Kalawate, Aparna S., 2023, Omorgus (Omorgus) khandesh (Coleoptera: Scarabaeoidea: Trogidae), a new species from India, along with an annotated catalogue of the Oriental and Palearctic species of the subgenus Omorgus Erichson, 1847, Zootaxa 5231 (5), pp. 501-522 : 503-506

Omorgus (Omorgus) khandesh Strümpher & Kalawate, new species

( Figs. 3–6 , 11–13 )

Type locality. “Khandesh” [= approximately the present-day Jalgaon , Dhule and Nandurbar districts of Maharashtra, India] .

Type material examined. India, Maharashtra province. Holotype ♁ ( ZSI-WRC, ENT-1/3217, specimen cleaned, aedeagus extracted) ( Figs. 3–5 ): “ T. R. Bell, | Khandesh. | [back, handwriting in pencil]: May [19]03 || Andrews | Bequest. | B.M.1922–221. [rectangle, faded white cardstock] || HOLOTYPE: Omorgus | (Omorgus) khandesh | Strümpher & Kalawate 2022 [rectangle, red cardstock]”.

Description of holotype (♁). Size. Length: 11.9 mm. Width: 6.1 mm.

Body shape. Strongly convex, elongate oval with almost parallel elytral margins, elytral profile convex, attaining maximum height behind the middle, strongly declivous posteriorly.

Colour ( Figs. 3–5 ). Matt black, surface of head, pronotum, legs, elytral margins and tubercles, and parts on the ventral side with light brown tomentose coating. Body setae mostly brown, to rust-brown.

Head ( Figs. 3–5 ). Clypeus obtusely triangular, with one raised oval tubercle, apex of clypeus pointed, margin reflexed, entire; surface sculpted with discrete and irregularly shaped punctures, these punctures close, each with a short stout seta, surface between punctures faintly tomentose. Frons raised with two large central tubercles, mediobasally with large flat nitid patch; surface and tubercles sculpted with discrete round punctures, punctures close, surface between punctures tomentose. Genal angles acute, recurved, deeply concave, surface sculpted with discrete and irregularly shaped punctures; gena and genal margin with scattered, straight setae. Eyes large and bulbous, barely visible in dorsal view. Antennal scape elongate, stout, with long straight brown setae; pedicel attached subapically; antennal club and setae fulvous. Setae around mouthparts dense, rust-brown.

Pronotum ( Figs. 3–5 ): Length of pronotum almost one third of elytral length, total pronotum width slightly narrower than elytron width, pronotum widest behind middle. Surface tomentose with discrete, rounded punctures, uniformly spaced, rather close, space between punctures less than diameter of punctures, each puncture bearing a short stout seta. Lateral margins broad and flat, explanate, attenuated anteriorly, margin evenly rounded over anterior-half towards anterior angle, anterior angle broadly obtuse, lateral margin emarginate in middle anterior to greatest width, there angle subobtuse, feebly extended laterally, then obliquely converging backwards, sinuate basally, posterior angles more distinct, almost right angled. Base of pronotum margined laterally, obliquely truncate behind posterior angles, base slightly projecting backward with distinctly produced posteromedian lobe, base slightly sinuated on either side of lobe. All margins smooth with short straight setae, edges thickly tomentose. Median discal area raised, stretching over anterior half of pronotum, flattened anteriorly, strongly declivous on sides. Pronotal disc with 2 broad elevated median longitudinal ridges. Ridges high, parallel, and not converging posteriorly. Median pronotal depression distinct, entire, fairly evenly wide, shallow anteriorly, deepest at posteromedian lobe. Medial basal tubercles distinct, slightly laterally offset, partially fused to median ridges, connected with lateral basal tubercles by faint marginal transverse ridge; anterior and lateral basal tubercles round; basal (larger) and apical (smaller) lateral tubercles large, fused forming distinct sinuous ridge on either side; short lateral carina present below lateral anterolateral ridge.

Scutellum ( Fig. 3 ): Hastate, slightly longer than wide, surface finely sculpted, mediobasally depressed, surface finely sculpted, apex slightly raised, distal half of scutellum and margins tomentose.

Elytra ( Figs. 3–4 ): Elongate, length of elytra equals of 2.4 pronotum length, lateral margins subparallel, smooth with tomentosity bearing row of fine short setae; sides wide, with low small round tubercles, these tubercles closely and crudely evenly spaced along elytral length, each with weak posterior tomentosity and 2–3 short stout setae. Humeral calli prominent bearing small tubercles with tomentosity and short setae, humeral angles obtuse, blunt. Sutural margin raised, surface with tomentosity, margin with raised elongate to round tubercles, separated, evenly distributed along margin; these tubercles smooth, shiny, each with posterior tomentosity and short setae, tubercles elongate and roughly of similar size for 0.75 elytral length, thereafter, becoming rounder and decreasing in size until barely discernible. Elytral costae distinct, even numbered costae more prominent than odd-numbered. Apical callosity present on fourth costal interval at top of elytral declivity. Even-numbered costae prominent, with distinctly raised, oval to round shiny tubercles (on intervals 2, 4 and 6), these tubercles close and regularly spaced along elytral length, roughly equal in size and height for 0.75 elytral length thereafter decreasing in size and height; costae 2 and 4 with basal 0.25 fused into partial ridges; tubercles on even-numbered costae each with tomentose posterior patches and short setae, anterior half of tubercle smooth and shiny; costae 8 with smaller, widely spaced, round tubercles, slightly raised, each tomentose with short setae. Odd-numbered costae marked by row of small round to oval tubercles and irregular shiny flat nitid areas (especially noticeable on intervals 1, 3 and 5; interval 2 without nitid patches); tubercles fairly evenly spaced along elytral length, size variable, each with tomentose patch; nitid areas slightly raised, irregular in shape. Intercostae marked by row of small round shiny punctures, puncture regularly spaced over length of elytra. Elytral surface matt, mostly smooth and without undulations and grooves; elytral profile convex, attaining maximum height approximately in the middle.

Metathoracic wings: Complete.

Legs ( Figs. 3–5 ). Protibia dorsally keeled, ending with small apical process, apex rounded; tibial spur stout, pointed forward, as long as four basal tarsomeres combined; tarsal segments smooth, without setae, fifth tarsomere with two claws, simple, equal; lateral tibial margin smooth, without teeth or indentations, dorsally outer tibial surface rugose and coarsely punctate; inner tibial surface (top lateral) smooth, glabrous, with round punctures running closely parallel to the outer and inner margins, punctures close, each with thin long seta; inner margin (lower half) punctate, punctures with long, dense setae; ventrally semi-flattened, submedially marginate, inner section smooth, glabrous without seate, outer section indumentose. Profemur large, widest basally, marginate on front face with row of straight forward pointing setae; ventral face with regularly spaced round punctures, each with single seta, surface indumentose; dorsal surfaces smooth. Procoxa narrow, elongate, flattened in front, surface rugose and punctuate. Meso- and metafemora slender, fore margins rounded without rows of setae; ventral faces with evenly spaced round punctures, each with a seta, space between punctures more than diameter of punctures; surface indumentose; dorsal surfaces smooth. Mesotibial and metatibial surfaces rugose, covered with thick indument, coarsely punctate, each puncture with a short seta, superomedial longitudinal carinae with row of stout setae; inner carinae with row of long slender setae; outer margin on apex of both meso- and metatibia with row of closely spaced stout backward pointing setae. Apex of mesotibia with two short tooth-like projections on inner margin beneath apical spurs. Mesotibia and metatibia with two apical spurs on inner margin; upper spur slightly longer and lower spur shorter than 1 st tarsomere. Mesotarsi and metatarsi indumentose with long setal brushes, tarsomeres 1–4 subequal in length, 5 th tarsomere as long as tarsomers 3 and 4 combined; fifth tarsal with two claws simple, equal.

Ventral aspects: Proepisterna: Surfaces rugose and coarsely punctate, thickly indumentose, punctures round to oval. Epipleura broad basally narrowing apically, concave along entire length, surface mostly smooth, weakly undulating, sparsely setose. Setae fine; inner margin with thick tomentosity. Mesoventrum medially densely punctate, slightly depressed, punctures large, medial area covered with thick tomentosity, laterally surface smooth, without puncture. Mesepisterna: Surface tomentose, punctate, punctures with seta. Metepisterna: Surface rugose and covered with indument, coarsely punctate, punctures irregular in shape. Metaventrum: Surface rugose and coarsely punctate, covered with indument, disc rhomboidal, flat, declivous behind without covering of indument. Abdominal ventrites: Five visible ventrites (IV–VIII); ventrite IV with rough surface, coarsely punctate; ventrites V–VII smooth, finely punctate, distal potion ridged; ventrite VIII course densely punctate, punctures shallow, distal margin marginate.

Male genitalia ( Figs. 11–13 ): Symmetrical, in profile slightly arched. Phallobasis divided and membranous dorsally ( Fig. 11 ); phallobasis short, length 3.4 aedeagus length (in profile) ( Fig. 12c ). Parameres applied closely to phallus and extended somewhat beyond phallus, parameres narrower than in O. (O.) rimulosus ( Haaf, 1957) (in profile; compare Fig. 12b with Fig. 15f ), apex of each sclerotised without membranous projection (compare Fig. 12a with Fig. 15e ). Phallus dorsally clearly concave anteriorly and projecting dorsolaterally forming two distinct humps (distinct in lateral view) ( Fig. 12d ) thereafter attenuated anteriorly, apex pointed, margin straight (not recurved) (compare Fig. 13i with Fig. 16j ).

Female. Unknown.

Diagnosis. Omorgus (O.) khandesh Strümpher & Kalawate , new species and O. (O.) rimulosus ( Haaf, 1957) , are morphologically very similar, but the former can be distinguished from the latter in having the tubercles on the even numbered costae close together, smaller, and not as highly elevated ( Figs. 3–4 ). Omorgus (O.) rimulosus ( Haaf, 1957) have these tubercles considerably larger, widely spaced along elytral length and more raised ( Figs. 7– 8 ). The male genitalia of the two species are distinctive with the most important differences found on the phalluses, parameres, and phallobases as described in the text (and as shown in Figs. 11–13 versus Figs. 14–16 ; see also Table 1 ). Both O. (O.) khandesh Strümpher & Kalawate , new species and O. (O.) rimulosus ( Haaf, 1957) have an external appearance similar to O. (O.) maissouri (Haaf 1954) ( Figs. 28–29, 31 ), but both can be distinguished from the latter by the appearance of the pronotum and elytra and the distinctive male genitalia.

Distribution. Known only from Western India.

Etymology. The species name is a noun in apposition referring to the Khandesh Region where the holotype was collected.

Figures

FIGURES 3–6. Omorgus (Omorgus) khandesh Strümpher & Kalawate, new species, holotype (ZSI-WRC). 3, habitus, dorsal view; 4, habitus, lateral view; 5, head and pronotum; 6, holotype labels.

FIGURES 11–16. Male genitalia in dorsal (11, 14) and lateral (12, 15) views, apex of median lobe (13, 16). Omorgus (Omorgus) khandesh Strümpher & Kalawate, new species, holotype (ZSI-WRC), 11–13. Omorgus (Omorgus) rimulosus (Haaf, 1957), holotype (NHMB), 14–16. a–j, for explanation refer to Table 1.

FIGURES 7–10. Omorgus (Omorgus) rimulosus (Haaf, 1957), holotype NHMB. 7, habitus, dorsal view; 8, habitus, lateral view; 9, habitus, ventral view 10, holotype labels.

FIGURES 28–31. Omorgus (Omorgus) maissouri (Haaf, 1954), holotype (MNHN). 28, habitus, dorsal view; 29, habitus, lateral view; 30, holotype labels; 31, aedeagus, dorsal and lateral view. Photos by Antoine Mantilleri, copyright MNHN.