Plutodes quadratus, Singh & Raha & Mallick & Kirti & Singh, 2023

Singh, Manpreet, Raha, Angshuman, Mallick, Kaushik, Kirti, Jagbir Singh & Singh, Navneet, 2023, A review of the genus Plutodes Guenée (Geometridae: Ennominae) from India with description of one new species, Zootaxa 5323 (4), pp. 499-523 : 514-520

Plutodes quadratus sp. nov.

( Figs 24–27 , 52–54 )

Holotype: 1 ♂, India, Chhattisgarh, Kabirdham dist., Bhoramdeo WLS, Chilpi FRH, 30.iii.2014, leg. A. Raha & party (8537/H10, NZCZSI).

Paratype: 1 ♀, India, Chhattisgarh, Korba dist., Lemru FRH, 24.iii.2014, leg. A. Raha & party (8536/H10, NZCZSI) .

Diagnosis: Although P. quadratus sp. nov. is slightly larger than P. transmutata and smaller than P. exiguifascia (Wingspan: 32 mm ( Hampson, 1893) ≈ Forewing length, 16 mm), these three closely allied congeners can be confusing in identification due to their external similarities. Plutodes quadratus sp. nov. is most reliably diagnosed by the shape of the distal patch on the forewing being roughly quadrate with the inner border, in both sexes, running straight onto the inner margin of the forewing after making an obtuse curvature near the costa. While, in the holotype female of P. exiguifascia ( Fig. 28 , the only existing specimen for comparison), the inner border of the forewing distal patch is slightly curved and not running straight onto the inner margin, i.e., the inner border is not making a right angle with the inner margin, rather bending outward to meet the inner margin. The inner border of the hindwing distal patch in both the sexes of P. quadratus sp. nov. has a distinct wider and deeper medial invagination than that in P. exiguifascia . Also, there is a small, distinct and acute projection at the end of the hindwing distal patch near the anal angle in both male and female specimens of P. quadratus sp. nov., but this is not evident in either of the other two species. In P. transmutata , the distal patches on both wings are narrower than in the other two species, irregular or “amoeboid”, more of kidney or bean-shaped. So, the yellow areas between the distal and basal patches on both wings in P. transmutata appear much broader than those of the other two congeners. The irregularity in distal patches in P. transmutata is particularly evident on the inner border of the patches where a medial, sharp invagination is present in case of both the wings. Moreover, in P. transmutata , the forewing distal patch ends much narrower at the inner margin. In the male genitalia, P. quadratus sp. nov. is distinct from that of P. transmutata by the shorter uncus with less spatulate tip, narrower valva with more sclerotized, upright and pointed saccular process (which is longer, weakly sclerotized and thumb-like in P. transmutata ), and distinctly broader saccus. In P. quadratus sp. nov. the aedeagus is straight, broad at base, gently narrowing at the middle, then again bulbous and ultimately terminating into bunch of setae-like structures at the apex. In female genitalia of P. quadratus sp. nov., corpus bursae is strongly sclerotized, spherical and evenly scobinated with minute spines; ductus bursae short, broad and well sclerotized, a spherical accessory sac with long duct, thrice the length of ductus bursae joined between the junction of ductus bursae and corpus bursae, posterior apophyses are two thirds the length of the anterior apophyses, anal papillae oval, setose and well sclerotized.

Description: Male: Head: vertex covered with light yellow scales, frons yellowish-brown; antennae unipectinate, a long apical section probably unpectinated, according to the female paratype and the related species (broken in male holotype); shaft and rami pale ochreous-brown, scape and pedicel pale buff-yellow; palpi short, not reaching the frons, upturned, apically blunt and covered with pale yellow scales. Thorax: collar and patagia covered with yellow scales, tegulae basally yellow, distal half rufous-brown; rest of the thorax rufous-brown dorsally, sternum and legs pale ochreous. Wing: Forewing length: ♂ 13 mm. Forewing ground colour pale yellow, moderately broad (length: breadth = 2:1), apex roundish, termen anteriorly straight from apex to middle, then gently curved to tornus; the basal patch small, rufous-brown bordered with thin black, somewhat triangular, with the costal border obliquely straight then making an obtuse angle running straight onto the inner margin; distal patch rufous-brown, bordered with thin silvery-black line, large, broad, roughly quadrate with the inner border, in both sexes, running straight onto the inner margin of the forewing after making an obtuse curvature near the costa (the curvature in male is sharper than female), the costal border running parallel to the costa makes a sharp angle near the apex (this corner of distal patch is more pointed in female) then runs toward the inner margin more or less parallel to the termen, making a wide and gentle curvature below M3 vein. Hindwing: ground colour pale yellow, termen anteriorly straight from apex to middle, then gently curved to anal angle (in female, termen is more roundish); basal patch rufous-brown, triangular, broader at costa, then gradually acute towards the anal angle with the outer border obliquely running straight onto the inner margin; distal patch rufous-brown, broad, somewhat kidney-shaped, outer border gently convex, inner border sinuous with a prominent medial depression; a small, distinct and acute projection at the end of the hindwing distal patch near the anal angle. Undersides of both wings have lighter shades of patches with shapes same as upperside, inside each patch bordered with an irregular, blurred black band. Abdomen: Dorsally rufous-brown with few yellow hair-scales, ventrally also rufous-brown, but with more yellow hair-scales. Genitalia: Uncus slender, apically spatulate; gnathos weakly sclerotized, plate-like; tegumen short, broad; valve narrow, elongated, costa slightly curved, apex round, sacculus weakly sclerotized, broad, short, about one-third the length of ventral margin with an upright, sclerotized, pointed saccular process; juxta weakly sclerotized, proximally broad, distally triangular with blunt tip; vinculum slender, elongated; saccus triangular, broad; aedeagus straight, broad at base, gently narrowing at the middle, then again bulbous and ultimately terminating into bunch of sclerotized setae-like structures at the apex.

Female: Forewing length: ♀ 14 mm. The pattern is same as male except the inner border of the distal patch on forewing is rounded near costa and not sharply angled as in the male holotype, and the upper right corner of this patch is pointed at apex and not rounded as in male. Genitalia: Papilla analis elliptical; anterior apophysis two-thirds the length of posterior apophysis; ostium round, weakly sclerotized; ductus bursae short, broad and well sclerotized, a spherical accessory sac with long duct, thrice the length of ductus bursae joined at the junction of ductus bursae and corpus bursae; corpus bursae strongly sclerotized, spherical and evenly scobinated with minute spines.

Etymology: The new species is named on the basis of the quadrate shape of the distal patch on the forewing which distinguishes it from the similar- looking P. transmutata and P. exiguifascia .

Distribution: India: Chhattisgarh.

Remarks: The new species inhabits lowland mixed deciduous forests having an altitude range of 300– 600 m.

Figures

FIGURES 24–28. Habitus of Plutodes spp. 24–25 P. quadratus sp. nov., male, Kabirdham Bhoramdeo WLS (Holotype), 26– 27, ditto, Female, Lemru FRH (Paratype); 28, P. exiguifascia, female, Pundaloya, Sri Lanka (Holotype). Ventral sides: 25, 27.

FIGURES 50–54. Genitalia of Plutodes spp. 50–51, P. transmutata, male, Bir: 50, ventral view, 51, aedeagus (vesica not everted); 52–53, P. quadratus sp. nov., male, Kabirdham Bhoramdeo WLS (Holotype): 52, ventral view, 53, aedeagus, 54, ditto, female (Paratype), Lemru FRH. (diagnostic characters indicated by black lines).