Paraxenoacria spinosa Rayhan & Jahan, 2024

Rayhan, Md Jahir & Jahan, Sayema, 2024, A new genus and species of Peleopodidae Hodges, 1974 (Insecta: Lepidoptera) from South-East Asia, Zootaxa 5523 (1), pp. 128-138 : 131-136

Paraxenoacria spinosa Rayhan & Jahan sp. nov.

Figs. 2–24

Type locality: Chittagong, Bangladesh.

Materials examined: Holotype, 1♂: BANGLADESH, CHITTAGONG, University of Chittagong campus (22°28′17.66″N 91°47′15.65″E), 4.iv.2024, Coll. Md. J. Rayhan (reared from the final instar larva on C. infortunatum plant) ; Paratype, 2♂♂: from the same location, 2.vi.2024 and 3.vi.2024, Coll. Md. J. Rayhan (reared from the larvae on L. indica & L. monopetala ). Deposited in the IMZUC .

Description: Adult male ( Figs. 2–4 , 5–7 , 23–24 ): wingspan 20–21 mm. Head with both frons and vertex ornamented with moderate sized pale brown scales with a whitish tinge and arranged somewhat roughly; antennae brownish with basal joint thickened, flagellomeres somewhat squarish, gradually tapering towards apex, largely filiform (though slightly serrated in distal half); labial palps slender and smoothly scaled, second and third joints similar in length, first joint pale brown, second joint brownish white above but smoky below up to two thirds, and third segment brownish but ringed with black basally; proboscis moderate in size, flattened, either galea distinct. Thorax brownish; forelegs short, smoky and pale; midlegs paler and rather orange yellow in color with tibiae having elongated hairs and a pair of tibial spurs, of which outer one shorter (almost half in length of the inner one); hindlegs pale yellowish orange, tibiae with elongated hairs, and two pairs of tibial spurs, in each of which outer spur shorter (almost half in length) compared to inner one. Abdomen darker brown above, paler below with creamy yellowish tinge, slightly flattened, and having a distinct tuft of medium sized pale scales on its posterior end.

Forewings elongate with costal margin gently arched, apex rounded, outer margin oblique, somewhat rounded, brownish in ground-color irrorated with dark scales, costal margin pale yellowish, cilia pale with dark irrorations and basally having a series of dark antecilial spots, a small elongated dark subbasal spot adjacent to base of discal spot, two ill-defined discal dots of which one at base of the cell and other at end of it, a faint trace of a postmedial line formed with indistinct dark patches, a distinct dark patch on inner margin near base. Hindwings shorter, rather broad, and having costal margin with shallow inward notch almost in middle ornamented with rough projecting scales on either side of notch causing it to appear as an excavation; coloration very much like forewings. Underside of both wings dark smoky brown with paler cilia.

Wing venation ( Fig. 10 ). Forewings with R 4 and R 5 stalked distally, CuP present. Hindwings with Sc curved parallel to notch on costa, M 3 and CuA 1 stalked basally on lower angle of discal cell.

Male genitalia ( Figs. 8–9 ) with uncus flattened, having tongue like setose socii laterally. Gnathos is developed with paired mesial bulbs having rows of spines. Tegumen narrow, elongated, well sclerotized and having downwardly directed digitiform paired outgrowths medially (of unknown homology). Transtilla membranous. Saccus broad, rather U-shaped. Juxta quadrate plate-like, and broad. Valva scapula shaped, divided into four lobes, and one sclerotized clavus with thick diamond-like numerous spines; costa of valva slightly arched, ending into a blunt and rounded lobe (appears twisted around the valva), followed by a distal lobe bending outward and appearing as shark teeth; saccular margin curved, deeply excavated in middle, having a rounded flap like lobe basally ornamented with long setae and distally ending into a sclerotized outwardly bent setose lobe (folding into a pocket) bearing a group of thick spines (more than six). Clavus finger like, originating from base of valve, thickly sclerotized, and ornamented with diamond-shaped thick spines. Aedeagus broad, trapezoid, flattened, and sclerotized, appears like skull of some reptiles; dorsally bearing a series of dentations; vesica with numerous small spines and a distinct patch of elongated cornuti.

Female: Unknown.

Distribution: Chittagong, Bangladesh.

Biology: More than 20 larvae and pupae ( Figs. 11–18 ) were observed from 7 species of unrelated plants. Among them, only three final instar larvae ( Figs. 11–13 ) were obtained for further rearing during the pre-monsoon and monsoon seasons between April to June, 2024. They were of around 40 mm in length, with a greenish groundcolor. Head large, reddish brown in color; prothoracic shield reddish brown and made of two lateral tridentate petal-shaped marks; mesothorax larger, both meso- and metathorax with single dark spot at the middle on dorsolateral side, followed by dark lateral stripes. Abdominal segments of similar pattern like the meso- and metathorax, but each segment with a pair of dark dorsolateral spots (instead of a single), fourth and fifth abdominal segments larger (the former largest and the latter darker with a brownish tinge).

They construct elongated rectangular silken cells ( Figs. 11–16 ) along the mid-rib (in case of elongated and narrow leaves like of Leea indica plants) or the thick veins branched off the mid-rib (in case of broad leaves like of Clerodendrum infortunatum plants) of their host-plant leaves made of transverse and oblique silk threads. Formation of such silken cells is similar to that in Acria species ( Saravanan et al 2020). Both anterior and the posterior end of the cells remain wide open, and the larva rest on either the mid-rib or the leaf vein (depending on the place of cell construction) within their silken cells, always keeping the head oriented towards the base of the leaves (based on field observations on more than 20 larvae). They come out during night time and feed by creating small holes near the cells (in case of mature instars), or making irregular broad scratches on the upper surface of leaves feeding on the upper epidermis (in case of early instars).

Pupation takes place within elongated spindle shaped loose silken cocoons ( Figs 19–21 ) in captivity, but within the silken cells in natural habitat ( Fig 17 ). The pupa ( Fig 22 ) is dark brown in color, slightly flattened, and broad anteriorly. Eyes moderate in size; frontoclypeus broad, squarish; labrum narrower; proboscis broad. Abdomen without lateral condyles, ten-segmented, of which the fourth segment broad, 4–6 segments loosely connected, spiracles and proleg scars well visible. The fifth segment bear a dorsal row of spines on its anterior edge. The fourth segment ventrally having a shallow medial depression on its anterior edge at the meeting point of the wing and other appendages.

Host-plants: The larvae appear to be polyphagous and were observed feeding on at least seven species of unrelated plants including Clerodendrum infortunatum L. ( Lamiaceae ), Litsea monopetala (Roxb.) Pers. ( Lauraceae ), Leea indica (Burm.f.) Merr. ( Vitaceae ), Syzygium sp. ( Myrtaceae ), Ixora sp. ( Rubiaceae ), and two other unidentified plant species.

Etymology: The species epithet spinosa refers to the presence of a group of thick spines on the distal saccular process of the valva.

Remarks: A comprehensive account on the biology combining the detailed morphological aspects (including chaetotaxy) will be published in a later communication. As the immature stages of the majority of the genera within not only Peleopodidae , but also all of Gelechioidea , are still unknown, we believe our elementary level information regarding the biological aspects of this new genus and species will not cause any bias or taxonomic complications in defining this new genus since almost all of the genera are defined by the characteristics of the adults rather than their immature stages.

Since no materials from other places were examined, the status of the morphotypes present in other places is unknown. The populations from India, Cambodia, and Malaysia have somewhat similar ground color and wing pattern like those from Bangladesh. The Singaporean population has a darker wings with all markings being prominent. On the other hand, those from Thailand, are rather paler and lack the basal dark patch on forewing inner margin. Likely, all of these populations reflect different geographic variations of this same species, or perhaps there remains several species yet to describe.

Figures

FIGURE 8. Male genitalia of Paraxenoacria spinosa sp. nov. holotype (a, details of uncus, gnathos, and tegumen; b, aedeagus; c, right valva).

FIGURES 9–10. Genitalia and wing venation 9, Male genitalia of Paratype, 10, Wing venation of the Holotype male

FIGURES 2–4. Adult of Paraxenoacria spinosa sp. nov. 2, Holotype male, 3, Paratype male, 4, Paratype male (underside of the right hand wings).

FIGURES 5–7. Paraxenoacria spinosa sp. nov., paratype male 5, Head, 6, Labial palps, 7, Mid- and hindlegs (red lines indicate the size of tibial spurs).

FIGURES 11–18. Immature stages of Paraxenoacria spinosa sp. nov., 11, Final instar larva of Holotype male on Clerodendrum infortunatum plant, 12, Late instar larva of Paratype male a on Leea indica plant, 13, Final instar larva of Paratype male b on Litsea monopetala plant, 14, Late instar larva on an unknown plant a, 15, Early instar larva on Ixora sp. plant, 16, Late instar larva on an unknown plant b, 17, Discarded pupal exuvium on Syzygium sp. plant, 18, Pupa of Paratype male b. (14–17 not reared).

FIGURES 19–22. Larva and pupa of Paraxenoacria spinosa sp. nov., 19–20, Pre-pupating larva of Holotype male, 21, Pupa within cocoon of the same (pink outline indicates the shape of cocoon), 22, Pupa (red lines indicate dorsal row of spines on the anterior edge of fifth abdominal segment).

FIGURES 23–31. Life habitus observations of genus Paraxenoacria gen. nov. from different countries 23, Holotype male of P. spinosa sp. nov. (Bangladesh), 24, Paratype male of P. spinosa sp. nov. (Bangladesh), 25, From Doi Pui, Thailand, 26, From Bentong, Pahang, Malaysia, 27, From Assam, India, 28, From Thomson Nature Park, Singapore, 29, From Tatai, Koh Kong, Cambodia, 30, From Thomson Nature Park, Singapore, 31, Acria sp. cf. A. emarginella (Donovan, 1804) from Pirojpur, Barisal, Bangladesh. (25–30 Paraxenoacria species, indetermined).