Sitotrogoides, Sohn & Ponomarenko & Sakamaki, 2019

Sohn, Jae-Cheon, Ponomarenko, Margarita G. & Sakamaki, Yositaka, 2019, A new genus of Pexicopiini (Lepidoptera: Gelechiidae) for “ Gelechia ” acanthopis Meyrick, 1932, with review of functional morphology of male genitalia in allied genera, Zootaxa 4638 (1), pp. 125-135 : 126-128

Genus Sitotrogoides gen. nov.

Type species: Gelechia acanthopis Meyrick, 1932 .

Diagnosis. Sitotrogoides is similar to Sitotroga in having the valva with a semiseparated sacculus in the male genitalia ( Figs 10 , 15 ). The type species of both genera, Sitotrogoides and Sitotroga , possess the aedeagus with a long caecum ( Figs 7 , 10 , 15 ) and lack the muscles m 3 in the musculoskeletal apparatus of the male genitalia. However, Sitotrogoides differs from Sitotroga by the presence of the separate forewing veins, Rs 4 and M 1, the separate hindwing veins, Rs and M 1 (Figs 3, 5); an arrow-like medial plate in gnathos ( Fig. 6 ), an elongate saccus, a setaceous valvella, the valva fused with the vinculum in the saccular area into an ankylosed sacculus +vinculum sclerite ( Fig. 11 ), the widely-spaced proximal parts of muscles m 2 and m 4 ( Figs 10, 11 ) in the male genitalia, and the shorter ovipositor ( Fig. 9 ) in the female genitalia.

Description. Head: labial palpi 2.3× longer than eye diameter; 2 nd palpomere with dense scales; 3 rd palpomere slender, acuminate apically. Antennae filiform in both sexes; scape without pecten.

Thorax: metatibia with dense scales. Forewing elongate, with narrowly-round apex. Forewing venation (Fig. 3) with Sc reaching margin at middle of costa; R arising from radius near midlength, nearly parallel to Rs 1; Rs 2 nearly parallel to Rs 1; Rs 3 and Rs 4 stalked at basal 1/3, curved to costa; M 1 nearly parallel to M 2, closer to stem of Rs 3 and Rs 4 except distal 1/3; M 3 divergent from CuA 1; CuA 2 slightly convergent to CuA 1 in basal 2/3; CuP present as folder in basal 3/4; 1A+2A with basal fork 1/4 length. Hindwing venation (Fig. 3) with Sc+R 1 reaching margin at distal 1/5 of costa, with oblique spur at basal 1/4; Rs stem arched at distal 1/3; Rs curved toward near wing apex; Rs and M 1 close in basal 1/6, divergent from each other; M 1 curved; M 2 slightly divergent from M 1 in distal half, closer to M 3 than to M 1; M 3 divergent from M 1; CuA 1 connate with M 3; CuA 2 slightly divergent from CuA 1; CuP closer to CuA 2 than to 1A+2A, incomplete medially; 1A+2A sinuous, with small basal fork; 3A close to 1A+2A, straight. Male sternite VIII ( Fig. 8 ) emarginated medially on posterior margin.

Male genitalia ( Figs 6–7 ) with lobate uncus; semi-circular gnathal plate; elongate valva, with linear zone of strong setae along ventral margin; saccus elongate, subtriangular; straight aedeagus with elongate caecum.

Female genitalia ( Fig. 9 ) with papillae anales elongate; apophyses slender; sclerotized band along ventral margin of ostium bursae fused with sclerotized ring of 8th abdominal segment; ductus bursae narrow, with sclerotization near ostium bursae; corpus bursae with two signa.

Description of male and female genitalia specific details see under the type species re-description.

Description of functional morphology of male genitalia. Musculoskeletal apparatus ( Figs 10–12 ) comprising seven paired muscles (m 1, m 2, m 4, m 5a, m 5b, m 6, m 22) and two unpaired muscle (m 21, m 28):

m 1 (musculus tergalis intersegmentalis 9–10) muscle from the lateral surface of the anterior part of tegumen to sclerotized semiseparate plate at the base of uncus;

m 2 (musculus gonopodalis externus dorsolateralis) muscle from the dorsal part of tegumen to the dorso-basal angle of valva and attached to the place of joining of the valva with tegumen;

m 4 (musculus gonopodalis externus dorsomedialis) muscle attached to the medial surface of anterodorsal margin of widened anterior part of tegumen and stretched to the medial side of saccular part of valva and to base of valvella;

m 5a (musculus phallicus externus posterior) muscle from the joined sclerite sacculus+vinculum to the lateral margin of the aedeagus caecum;

m 5b (musculus phallicus externus posterior) muscle from ventral surface of saccus to the apex of aedeagus caecum;

m 6 (musculus phallicus externus anterior) muscle stretched from the lateral margin of the saccus to the ventral surface of aedeagus;

m 21 (musculus phallicus internus longitudinalis) muscle placed within inflated basal part of the aedeagus;

m 22 (musculus tergosternalis intrasegmentalis 9) muscle from anterior margin of vinculum to external surface of anterodorsal angle of tegumen;

m 28 (musculus phallicus internus trasverses) muscle of the balbus of ejaculatory dustus aedeagus.

Etymology. The generic name is derived from a similar genus, Sitotroga with a Greek suffix, ‘- oides ’, meaning “like”.

Figures

FIGURES 10–12. Musculoskeletal apparatus of male genitalia in Sitotrogoides acanthopis (Meyrick, 1932). 10, lateral view; 11, uncus, tegumen, valva, position of muscles m 1, m 2 and m 4, medial view; 12, phallic muscles, ventral view, valvae removed partly. Arrows and numbers in circles indicate diagnostic characters of the tribe Pexicopiini (see the main text). Abbreviations: m 1, m 2, m 4, m 5a, m 5b, m 6, m 21, m 22 —muscles; aed—aedeagus, b.vlv—base of valva, c—caecum, gn—gnathos, vlv—valva, vlvl —valvella, vnc—vinculum, sacc—saccus, scl—sacculus, tg—tegumen, un—uncus.

FIGURES 13–15. Musculoskeletal apparatus of the male genitalia. 13, Platyedra subcinerea (Haworth, 1828), lateral view; 14, ditto, basal part of tegumen and valva with attached muscles, medial view; 15, Sitotroga cerealella (Olivier, 1789), lateral view. Arrows and numbers in circles indicate diagnostic characters of the tribe Pexicopiini (see the main text). Abbreviations: m 3 —muscles, ccl—cucullus, soc—socii; others as in Figures 10–12.

FIGURES 6–9. Genitalia and abdominal segments of Sitotrogoides acanthopis (Meyrick, 1932). 6, male genitalia, ventral view; 7, aedeagus; 8, abdominal segment VI–VIII, terga in left, sterna in right; 9, female genitalia.