Idaea proximaria (Leech, 1897)

Cheng, Rui, Xue, Da-Yong, Jiang, Nan & Han, Hong-Xiang, 2023, Review of the Idaea proximaria complex (Lepidoptera, Geometridae, Sterrhinae) with descriptions of four new species, ZooKeys 1169, pp. 293-305 : 293

Idaea proximaria (Leech, 1897)

Figs 3-7 , 16-19 , 24-26 , 30

Chrysocraspeda proximaria Leech, 1897: 106. Syntypes 2♂, China (western): Moupin (NHMUK).

Ptychopoda proximaria : Prout 1913: 101.

Sterrha proximaria : Prout 1934: 414.

Idaea proximaria : Scoble 1999: 504.

Material examined.

China: Shaanxi (IZCAS): 1♂, Ningshan, Huoditang , 1497 m, 29-31.VII.2018, leg. Zhang Xinyi ; 1♂ 1♀, Taibai, Huangbaiyuan , 1279 m, 15-17.VII.2018, leg. Zhang Xinyi ; 2♂, Foping, Yueba , 1052 m, 1-3.VIII.2018, leg. Zhang Xinyi ; 1♀, Ningshan, Guanghuojie, Baohuzhan , 1189 m, 26-28.VII.2014, leg. Liu Shuxian , slide no. Geom-5167; 11♂ 1♀, Ningshan, Guanghuojie , 1101 m, 27-28.VII.2018, leg. Zhang Xinyi , slide no. Geom-5928 (♂); 13♂ 3♀, Shangnan, Jinsixia , 766-777 m, 23-25.VII.2013, 16-19.VII.2017, leg. Cui Le , slide no. Geom-5136 (♂), 5137 (♂), 5138 (♀), 5163 (♂), 5164 (♂), 5165 (♂), 5166 (♂), 5168 (♀), 5184 (♂), 5185 (♂). Hubei (IZCAS): 13♂ 2♀, Shennongjia, Chaoshuihe , 860 m, 21-23.VI.2019, leg. Cheng Rui. Sichuan (IZCAS): 1♂ 4♀, Emeishan, Qingyinge , 800-1000 m, 19.VI.-15.VII.1957, leg. Zhu Fuxing et al., slide no. Geom-5162 (♀); 5♂, Mianzhu , Jiulongshan, Shizipo, 810 m, 29-31.VII.2016, leg. Cui Le , slide no. Geom-4134 (♂), 5158 (♂), 5186 (♂); 8♂ 5♀, Baoxing, Fengtongzhai, Dashuigou, 1590 m, 1-5.VIII.2016, leg. Cui Le, slide no. Geom-4135 (♀), 5180 (♂); 3♂ 1♀, Chongzhou, Jiguanshan, Anzihe, Shaoyaogou, 1556 m, 11-16.VII.2016, leg. Cui Le, slide no. Geom-4141 (♂); 11♂ 12♀, Mianzhu , Dajianping, 877 m, 17-18.VII.2019, leg. Zhang Xinyi ; 6♂ 7♀, Wenchuan, Huangjiacun , 1033 m, 13-14.VII.2019, leg. Zhang Xinyi ; 13♂ 11♀, Pengzhou, Dingjiawanping , 1088 m, 15-16.VII.2019, leg. Zhang Xinyi ; 6♂ 7♀, Tianquan, Lianglukou , 1405 m, 1-2.VII.2019, leg. Zhang Xinyi.

Diagnosis.

As Prout (1913, 1938) stated, I. proximaria is similar to I. craspedota (Fig. 14 ) in the wing pattern, but the latter lacks the areole on the forewing. The genitalia of the two species are quite different: the uncus is truncate with tiny protuberances in I. proximaria , but tapering and pointed in I. craspedota (Fig. 23 ); the gnathos is developed in I. proximaria , but only bears a blunt median process in I. craspedota ; the valva has different decorations in I. proximaria , but is very narrow and simple in I. craspedota ; the anellus is very large in I. proximaria but reduced in I. craspedota . In the female genitalia, the ductus bursae of I. proximaria is very broad but quite narrow in I. craspedota (Fig. 34 ).

Redescription.

Head. Antennae ciliate in male, filiform with sparse cilia in female, cilia shorter in female. Frons dark, with sparsely scattered brown scales, not protruding. Labial palpus dark brown on dorsal side and paler on ventral side, third segment ~ 1/2 length of second segment, extending beyond frons. Vertex pale brown.

Thorax. Tegula pale brown. Hind leg in male modified; hind tibia dilated; first segment of tarsus very broad and flat, shaped like a bird’s wing, covered with darkish scales, the inner side bearing a bunch of long hair-pencils from base of tibia to tip of tarsus, other tarsomeres vestigial. Hind tibia in female normal, with one pair of terminal spurs. Forewing length: male 9-11 mm, female 9-12 mm. Wings pale brown, diffused with dark scales. Forewing with costa straight, distal one-third convex; apex protruding; outer margin slightly convex. Forewing with costa dark purplish brown; antemedial line vague, discernible by a small patch on costal margin; postmedial line sinuous, appearing as black dots on veins, vague between veins; terminal margin a narrow dark purplish brown band; an indistinct darkish patch present at middle of hind margin. Hind wing with outer margin slightly protruding on vein M3; postmedial line and terminal margin same as on forewing. Both wings with black discal spot. Fringes reddish brown, decorated with dark scales on vein ends. Underside: paler than upperside; forewing with basal part diffused with greyish scales; postmedial line more continuous than on upperside; terminal band much narrower.

Abdomen. Dorsal side pale brown, decorated with dark brown scales, dense on intersegment; ventral side pale brown.

Male genitalia. Uncus spatulate, with two tiny lateral and ventral protuberances at tip. Gnathos developed, tongue-like. Valva long and slender, apex rounded and setose; dorsal margin almost straight to slightly convex, with a subapical mound-like protrusion; ventral margin with a blunt central protrusion. Anellus a very large sclerite, posterior margin smooth and strongly protruding, lateral margin with lower half spinulose. Saccus blunt. Aedeagus short, terminal two-thirds sclerotised and stout, cornutus with one or two spines.

Female genitalia. Ovipositor lobes with small ventral protrusion. Apophyses posteriores ~ 2 × length of apophyses anteriores. Region around ostium strongly sclerotised, lamella postvaginalis and antevaginalis irregularly shaped. Ductus bursae very long and broad, wrinkled, with a large scobinate area, anteriorly membranous, the middle part decorated with long spines, posteriorly, with a well sclerotised pouch-like process; an elongate diverticulum present, diverging posteriorly. Corpus bursae small, with a rounded spinose patch.

Distribution.

China (Shaanxi, Hubei, Sichuan).

Remarks.

It has not been possible to examine the genitalia of the syntypes of I. proximaria since neither of them has been dissected. However, since the syntypes and the complete series in the NHMUK (the Natural History Museum, London, United Kingdom) are from Sichuan and we have only seen one species in the complex from Sichuan province, it is reasonable to assume that this is the species described by Leech.

In I. proximaria , the aedeagus has a varying number of cornuti on the vesica. For example, some only have one large bent spine (Fig. 24 ); some have two spines of equal length (Fig. 25 ), or of different sizes (Fig. 26 ). The conditions of one spine and two equally sized spines occur among the specimens collected from Shizipo, Sichuan province, and that of two spines of different sizes occur among specimens collected from Jinsixia, Shaanxi province. Other differences could not be found in the armament of the male genitalia (Figs 16-19 ) or in the female genitalia and wings (Figs 3-7 ). To determine whether these differences are of intraspecific variations or different species, four fresh specimens from Jinsixia, Shaanxi province were used to obtain barcoding sequences; of these specimens, LEP M 31611 and 31619 bear two equal-sized spines, LEP M 31612 bears two differently sized spines, and LEP M 31623 is a female. The result (Fig. 15 ) shows that no genetic distance can be found between the four specimens; thus, these specimens are considered to belong to the same species. The genetic distance between I. proximaria and I. craspedota is 8.36% (Fig. 15 ).

Most public Idaea sequences on BOLD were downloaded, including 32 sequences from China, and a NJ tree was constructed (Suppl. material 1). In the NJ tree, I. proximaria is clustered with two unnamed specimens with very low support values, which means this relationship is unreliable. Through calculating pairwise distances, I. politaria ( Hübner) of inquinata species group was found as the nearest related species with a genetic distance 6.15%; however, it is very far from I. proximaria on the NJ tree. It can be inferred that, on the basis of the public COI sequences available on BOLD, the closest species to I. proximaria has not yet been found.

In the present work, the main purpose of DNA barcoding is to identify whether I. proximaria has intraspecific variation; the results of NJ tree for a large number of species are not included, which is beyond the scope of this work, and only three sequences of I. craspedota , with similar wing patterns, are included (Fig. 15 ).

Figures

Figures 1 - 15. (1 - 2) Male hind tibia and tarsus of Idaea proximaria 1 lateral view 2 medial view. (3 - 14) Adults of Idaea proximaria complex 3 - 7 I. proximaria 3 male, Jiguanshan, Sichuan 4 female, Baoxing, Sichuan 5 - 7 Jinsixia, Shaanxi 5 - 6 male 7 female 8 - 9 I. rectangularis sp. nov. 8 holotype, male, IZCAS 9 paratype, female, IZCAS 10 I. rectispina sp. nov., holotype, male, IZCAS 11 - 12 I. setosa sp. nov. 11 holotype, male, IZCAS 12 paratype, female, IZCAS 13 I. linearis sp. nov., holotype, female, IZCAS 14 I. craspedota. 15 Neighbour-Joining (NJ) tree of selected Idaea proximaria complex based on the Kimura two-parameter model. Scale bar: 1 cm (3 - 14).

Figures 16 - 27. (16 - 23) Male genitalia of Idaea proximaria complex 16 - 19 I. proximaria 16 - 17 Shizipo, Sichuan 18 - 19 Jinsixia, Shaanxi 20 I. rectangularis sp. nov., holotype 21 I. rectispina sp. nov., holotype 22 I. setosa sp. nov., holotype 23 I. craspedota. (24 - 27) Aedeagus of I. proximaria complex 24 - 26 I. proximaria 24 Dashuigou, Sichuan 25 Shizipo, Sichuan 26 Jinsixia, Shaanxi 27 I. rectangularis sp. nov., holotype. Scale bars: 1 mm.

Figures 28 - 34. (28 - 29) Aedeagus of I. proximaria complex 28 I. rectispina sp. nov., holotype 29 I. setosa sp. nov., holotype (30 - 34) Female genitalia of I. proximaria complex 30 I. proximaria 31 I. rectangularis sp. nov., paratype 32 I. setosa sp. nov., paratype 33 I. linearis sp. nov., holotype 34 I. craspedota. Scale bars: 1 mm.