Psilocladia indica M. Singh, Lenka & N. Singh, 2025

Singh, Manpreet, Lenka, Rajesh, Chatterjee, Pallab & Singh, Navneet, 2025, A new species of genus Psilocladia Warren from India, bridging the boundaries of Africa and Asia (Lepidoptera: Geometridae: Ennominae), Zootaxa 5594 (2), pp. 316-324 : 317-323

Psilocladia indica M. Singh, Lenka & N. Singh , sp. nov.

urn:lsid:zoobank.org:act:00D5F0FA-4745-488F-8604-009E992E6278

( Figs. 1–4 , 9–10, 12–13 )

Material examined:

Holotype: ♂, India, Arunachal Pradesh, West Kameng district, Upper Singchung , 29.iv.2022, Alt. 1533.4 m, 27.1949ᵒN 92.4829ᵒE, D. Mitra leg.

Paratypes (1 ♂, 9 ♀): India, Odisha, Angul district , 1 ♂, 4 ♀, Karadei, 3.iv.2022, Alt. 79.4 m, 20.1053ᵒN 85.0826ᵒE, R. Lenka leg. Arunachal Pradesh, West Kameng district , 1 ♀, Kalakthang, 10.vi.2022, Alt. 345.3 m, 27.1041ᵒN 92.1122ᵒE, D. Mitra leg. ; 2 ♀, Tenga, Husi gaon, 12.vi.2023, Alt. 1282 m, 27.2196ᵒN 92.6098ᵒE, P. Chatterjee leg. ; 1 ♀, Tenga, Helipad, 15.vi.2023, Alt. 1624 m, 27.1995ᵒN 92.5019ᵒE, P. Chatterjee leg. ; 1 ♀, Dirang, Sagar basti, 24.vii.2023, Alt. 1741 m, 27.3316ᵒN 92.2661ᵒE, P. Chatterjee leg.

Diagnosis ( Figs. 1–4 ): Externally, P. indica sp. nov. resemble P. obliquata ( Fig. 5 ). However, the new species is significantly smaller in size with a forewing length of 10–13 mm compared to approximately 18 mm in P. obliquata . Psilocladia indica sp. nov. is distinct by the forewing with a broad, obliquely straight medial line from inner margin to lower edge of the cell, then narrower towards the costa with a distinctive inward curve within the cell and a conspicuous dark brown triangular patch on the inner margin; hindwing with a more prominent antemedial line. Whereas in P. obliquata , medial line of forewing is partially double between the inner margin and the lower edge of the cell and subsequently running obliquely straight to the costa; also a postmedial series of dark brown spots on each vein from the costa to CuA2, which is absent in P. indica sp. nov.

In male genitalia, P. indica sp. nov. ( Figs. 9–10 ) is distinct from P. obliquata ( Fig. 11 ) by its symmetrical pair of furca, arising straightly from their bulbous bases, as well as a markedly longer uncus and a shorter medial process of the gnathos. In contrast, male genitalia of P. obliquata bear basely curved, asymmetrical furca: the left one significantly longer.

In the female genitalia ( Figs. 12–13 ), P. indica sp. nov. is distinct from P. obliquata ( Fig. 14 ) by its significantly larger signum, which has a small medial concavity and transverse ends terminating in spines, giving it a somewhat groundnut-shaped appearance. In P. obliquata , the signum is oval, distinctly smaller, with a large medial concavity and small spines around its periphery.

Furthermore, P. indica sp. nov. is distinct from its other three congeners, P. repudiosa ( Fig. 6 ), P. diaereta ( Fig. 7 ), and P. loxostigma ( Fig. 8 ), by its dark brown wings that are basally infused with white. In P. indica sp. nov., the outer margin of the hindwing exhibits reduced crenulation with a protruded apex at Rs. In contrast, P. repudiosa displays less extended Rs into a tail but has deep crenulations along the outer margin. In P. diaereta and P. loxostigma , there is an excision between Rs and M3, which is more pronounced without a medial protrusion in P. diaereta and shallower with a noticeable medial protrusion in P. loxostigma .

Description: Head: Antennae simple and lamellate in both sexes. The frons yellow. Labial palpi are porrect and reach beyond the frons, with terminal segment gently drooping. The vertex is covered with long yellow scales. Ocellus well-developed and marked by pale yellow piliform scales. Thorax: The notum covered with smooth pale white scales. Patagia pale brown, while tegulae are white. The pleuron and sternum are pale brown. Legs feature a bunch of hair-pencil scaled basally on the fore tibia. The hind tibia has two pairs of spurs. The forewing length is 10–11 mm in males and 11–13 mm in females. Wings have a pale brown ground color, infused with grey scales. The forewing is elongated with a straight costa up to two-thirds then well arched with a subacute apex. The outer margin is more or less straight, the anal margin round and somewhat lobed, and the inner margin is slightly sinuous in the middle.

Forewing with transverse lines reddish brown; the antemedial line is short obliquely straight running from the inner margin to the edge of the cell; medial line is broad between the inner margin and the lower edge of the cell, then appears slender with an inward curve between the lower edge of the cell and costal margin. There is a broad prominent triangular or trapezoid reddish-brown patch at the inner margin of submarginal area. Sometimes an indistinct postmedial line, dark and highly curved near costal margin, runs obliquely straight to join the reddish-brown triangular or trapezoid patch; the basal part along the inner area is infused with white; cilia are brown.

Hindwing with costal margin straight, and the outer margin is produced at Rs. The medial and postmedial lines are more or less obliquely straight, with the latter originates from a small, dark brown triangular patch at the costa and slightly curved just before meeting the inner margin; cilia are the same as forewing. Discal spot absents in both wings. The underside of both wings is dark brown but in forewing, the area from basal to the outer margin above M3 is faded. The transverse line is darker. The hindwing has a postmedial line partially doubled from inner margin to CuA2. Abdomen: The dorsum is pale brown, mixed with pale yellow and black scales. The anal tuft is pale yellow.

Male genitalia ( Figs. 9–10 ): The uncus is broad at the base, elongated, slender with a pointed apex. The lateral arms of the gnathos are weakly sclerotized, and the median process is short with numerous setal hairs. The valva is simple, broad, with a uniformly convexed ventral margin and an apex that is somewhat acute with slightly pointed apices; the costa is broad, and slightly incurved medially. A pair of symmetrical furca, arise straightly from the bulbous base. The aedeagus is short and slender with an apically acute extension; the vesica is membranous and has a weakly sclerotized patch.

Female genitalia ( Figs. 12–13 ): Papillae anales are somewhat tapered and setosed. Posterior apophyses are typically long and slender. Anterior apophyses are extremely reduced and acute with pointed tips. The ductus bursae is slender and tubular. Corpus bursae has a broad, tube-like proximal part with moderate sclerotization where the ductus bursae conjoins with the corpus bursae. The posterior part is membranous, bearing a large signum with small medial concavity. The transverse ends of the signum terminate in a spine, giving it a groundnut-shaped appearance, with a few central minute spines scattered inside.

Bionomics: Psilocladia indica sp. nov. is found in a variety of ecosystems ( Figs. 15–18 ) ranging from lowland tropical forests to wet temperate forests, at altitude range up to 1800 m. These habitats are dominated by several prominent plant families, including Rosaceae , Ericaceae , Passifloraceae , Brassicaceae , Lamiaceae , Melastomataceae , Fabaceae , Betulaceae , Asteraceae , and Verbenaceae . The Eastern Ghats ( India) too are markedly different from the habitats of its congeners in the Afrotropic. African species of Psilocladia inhabit diverse ecosystems, such as coastal forests to grasslands ( P. obliquata ) ( Mapcarta 2024), tropical rainforests ( P. loxostigma and P. repudiosa ) ( Linder et al. 2012) and urban areas with forest patches ( P. diaereta ) ( Kenya forest services (2024)).

Distribution: The new species is distributed in the Eastern Ghats (Odisha) and Himalayas (Arunachal Pradesh), India.

Etymology: The name of the species represents country of origin ‘India’.

Figures

FIGURES 1–4. Adults of Psilocladia indica sp. nov.: 1, Male, Holotype (Upper Singchung, Arunachal Pradesh); 2, Female, Paratype (Karadei, Odisha); 3, Male, Paratype (Karadei, Odisha); 4, Female, Paratype (Husigaon, Arunachal Pradesh). a. dorsal sides; b. ventral sides.

FIGURES 9–14. Genitalia structure of Psilocladia spp.: 9, P. indica sp. nov., male, HT (Upper Singchung); 10, P. indica sp. nov., male, PT (Karadei); 11, P. obliquata, male (Mpumalanga, South Africa) (Image source, Dr. P. Sihvonen); 12, P. indica sp. nov., female (Karadei); 13, P. indica sp. nov., female (Husigaon); 14, P. obliquata, female (KwaZulu-Natal, Bulwer, South Africa) (Image source, Dr. P. Sihvonen). a, genitalia capsule; b, aedeagus.

FIGURES 5–8. Adults of Psilocladia spp.: 5, P. obliquata, Male, Holotype (South Africa); 6, P. repudiosa, Male, Holotype (Cameroon); 7, P. diaereta, Male, Holotype (Kenya); 8, P. loxostigma, Male, Holotype (Congo). a. dorsal sides; b. ventral sides (for figures 5–8 © NHMUK).

FIGURES 15–18. Distribution map and collection habitats: 15, Map showing global distribution of species of Psilocladia species; 16–18, Collection habitat of P. indica sp. nov.: 16, Karadei, Angul dist., Odisha; 17, Upper Singchung, West Kameng dist., Arunachal Pradesh; 18, Husigaon, West Kameng dist., Arunachal Pradesh.