Megaxyela fulvago Stephan M. Blank & Katja Kramp & David R. Smith & Yuri N. Sundukov & Meicai Wei & Akihiko Shinohara 2017, sp. nov.

Megaxyela fulvago Blank, Shinohara & Wei sp. nov.

urn:lsid:zoobank.org:act:DF04584F-B33D-42A7-836D-E758A66F4081

Figs 4A–G, 11B, 12B–C, 13B

Megaxyela gigantea – Takeuchi 1940: 484 (misidentification). ― Maa 1949: 30 (misidentification). Megaxyela sp. 2 – Shinohara et al. 2017: fig. 15 (phylogenetic analysis). — Blank et al. 2017: 115.

Diagnosis

The red brown head, prothorax and mesothorax are unique to this species.

Etymology

The Latin noun fulvago indicates the predominantly pale brown color of this species.

Type material Holotype

CHINA: ♂: “[CHINA: Hunan] Mt. Yunshan 1250 m [alt.] 26°39′ N, 110°37′ E nr. Wugang 12.IV.2012 [leg.] A. Shinohara ”; “ DEI-GISHym 5236 ”; [red:] “Holotype Megaxyela fulvago det. SMBlank & AShinohara 2015” (CSCS).

Paratypes (6 ♀♀, 6 ♂♂)

CHINA: 1 ♀, 5 ♂♂, same collecting data as holotype, DEI-GISHym 5235, 5237–5239, 5751–5752 (5237, 5239, 5751–5752 used for barcoding) (SDEI, NSMT); 1 ♀, Jiangsu Sheng, Nanjing, 32.06° N, 118.78° E, 1 May 1985, Jinniang leg. (CSCS); 2 ♀♀, 1 ♂, Jiangsu Sheng [“Prov. Kiangsu”], Zhenjiang [“Chinkiang”], 32.20° N, 119.43° E, 24 Apr.–1 May 1918 (IZCAS) (Takeuchi 1940; Maa 1949; images for re-identification provided by Yang Ganyan); 1 ♀, Zhejiang Province, Kaishan Laodian, Tianmushan, Lin’an, 30.343° N, 119.435° E, 1140 m alt., 10 Apr. 2014, Liu Ting and Yu Xinjie leg., CSCS14012, DEI- GISHym 30882 (specimen used for barcoding) (CSCS); 1 ♀, same locality, 1110 m alt., 14 Apr. 2016, Li Zejian, Liu Mengmeng and Chen Zhiwei leg., CSCS16143, DEI-GISHym 30883 (specimen used for barcoding) (CSCS).

Description Female

COLOR. Body red brown with black-and-white pattern, black parts partly with bronze tinge (Fig. 4A). Head and thorax red brown (specimen 30882 with diffuse transverse stripe on vertex – artifact?), posterior half of metanotum and ventral half of metepisternum infuscate. Scape red brown, pedicel black, flagellum dark brown. Abdomen in dorsal view black with continuous white bands laterally on terga 2–4, each 0.15–0.20 × as wide as tergal width, tergum 8 with narrower lateral white band, ventral portions of terga 2–4 and 8 completely white, terga 5–6 narrowly and tergum 7 broadly white along ventral margin, terga 9+10 brown with small dark spot dorsolaterally. Sterna white. Valvifer 2 and valvula 3 red brown, membrane between valvifer 2 and valvula 3 pale (Fig. 11B). Fore and mid legs pale red brown. On hind leg, coxa red brown, infuscated laterally in middle and dorsally, trochanter and trochantellus pale red brown, femur brown dorsally and red brown ventrally, tibia and tarsus brown. Wings weakly yellow stained, venation and pterostigma yellow brown.

MORPHOLOGY. Body 11.4–13.0 mm, fore wing 14.9–15.4 mm long. POL: OOL: OCL = 1.0: 2.2–2.4: 2.2–2.3. Interantennal distance 1.0–1.1 × as wide as distance between torulus and eye margin, malar space 0.4–0.5 × as wide as interantennal distance. Eye 1.3–1.4 × as long as wide, frons at dorsal edge of antennal toruli 1.7–1.8 × as wide as maximum diameter of eye. Synantennomere 3 4.5–4.9 mm, filament 1.1 mm, with 8–9 articles.Article 3 of maxillary palp 0.5–0.6 mm long. Ovipositor sheath 3.30–3.50 mm long, valvula 3 1.9–2.3 × as long as wide. On hind leg, femur 4.9–5.0 mm, tibia 5.6–6.0 mm, tarsus 4.1–4.3 mm, tarsomere 1 4.5–5.1 × as long as wide, longer distal spur of tibia 0.70 × as long as tarsomere 1, subapical tooth of claw stout and little shorter than apical tooth (Fig. 4B; similar to Shinohara 1992: fig. 4D). Face and vertex with areolate surface microsculpture, dull, interantennal area and frons above antennal toruli with scattered, shallow, 50 µm large pits (similar to Fig. 4G), gena weakly coriarious, shining. Mesoscutum and mesoscutellum homogeneously areolate. Mesepisternum weakly coriarious and shining, with scattered pits. Metatarsomere 1 dorsally and dorsolaterally very sparsely setose, ventrally and ventrolaterally densely setose, setae 150–200 µm long ventrally (Fig. 4B). Pulvilli absent on article 1 of metatarsus, present on articles 3–4, presence ambiguous for article 2, on article 4 pulvillus 50 µm long. Basal and medial sections of valvula 3 of ovipositor sheath convex dorsally, almost straight ventrally, preapical section concave on dorsal and ventral edge, medial to preapical section of dorsal margin with setae up to 200 µm long, ventral margin with setae up to 100 μm long (Fig. 11B). Ovipositor about 2.4 mm long, weakly curved ventrally, valvula 1 and valvula 2 with bulbous areas in middle, without ctenidia (Fig. 12B–C). Valvula 1 in distal 0.7 with very narrowly spaced, subparallel, straight, vertical annuli, ventral margin in distal 0.3 bearing small serrulae. Valvula 2 in distal 0.6 with narrowly spaced annuli, distal 0.3 of dorsal edge of valvula 1 with small denticles.

Male

COLOR. Similar to female (Fig. 4E–G). Metepimeron red brown or predominantly infuscate. Ventral portions of terga 5–7 predominantly white. Subgenital plate and genitalia red brown. On hind leg, coxa sometimes completely black laterally, trochanter and trochantellus red brown, femur black dorsally and medially, dark red brown ventrally and laterally, tibia and tarsus black (Fig. 4C–D).

MORPHOLOGY. Body 8.8–10.7 mm, fore wing 11.3–12.8 mm long. POL: OOL: OCL = 1.0: 1.6–1.7(– 1.9): 1.7–1.9(–2.0). Interantennal distance 0.9–1.1 × as long as distance between torulus and eye margin, malar space 0.5 × as wide as interantennal distance. Eye 1.3–1.4 × as long as wide, frons at dorsal edge of antennal toruli 1.6–1.8 × as wide as maximum diameter of eye. Synantennomere 3 (3.6–)4.0– 4.6 mm, filament 1.0– 1.1 mm and with 8–9 articles (one male with left filament 0.8 mm long, 6 articles, right filament 1.0 mm long, 8 articles). Article 3 of maxillary palp 0.4–0.5 μm long. On hind leg, femur 3.7–4.2 mm, tibia 4.5–5.2 mm, tarsus (3.8–) 4.1–4.4 mm, tarsomere 1 4.9–5.5 × as long as wide, longer distal spur of tibia 0.60 × as long as tarsomere 1. Claws and microsculpture similar to female (Fig. 4D).

Subgenital plate bluntly pointed at apex. Valviceps of penis valve distally parabolically rounded, basal 0.3 of upper side expanded to a round lobe coiled laterally, medial 0.3–0.8 of upper edge shallowly convex, with numerous small teeth. Distal 0.7 of valviceps with long setae, most dense in medial lower portion of valviceps (Fig. 13B).

Remarks

Megaxyela fulvago sp. nov. is most similar to M. gigantea regarding color and structure. In both species, terga 2–4 are extensively white on the dorsolateral and ventral portion. This pattern is absent in M. euchroma sp. nov. and in most of the Nearctic species. White is present on the dorsal side of only terga 2–3 in M. parki, M. pulchra sp. nov. and M. togashii, as well as in the Nearctic M. major. Megaxyela fulvago sp. nov. and M. gigantea share the dull, minutely areolate and shallowly pitted face. A rugose surface structure is absent from the frons, which has been observed in the other East Asian species. Megaxyela fulvago sp. nov. and M. gigantea are primarily discriminated by color: head, prothorax and mesothorax are completely red brown in M. fulvago sp. nov., but these parts bear an extensive dark brown to black pattern in M. gigantea. The antennal filament of females is longer in M. fulvago sp. nov. (1.1 mm) than in M. gigantea (0.8 mm), and sometimes it is subdivided into fewer articles in M. fulvago sp. nov. (♀: 8–9; ♂: usually 8–9) than in M. gigantea (♀: 9; ♂: 9–10). The relative distance of POL: OOL: OCL differs weakly in males (1.0: 1.6–1.7[–1.9]: 1.7–1.9[–2.0] and 1.0: 1.8–2.0: 2.0–2.2, respectively). The metatarsomere 1 of males is 4.9–5.5 × as long as wide in M. fulvago sp. nov. but 4.6–5.0 × in M. gigantea. The female of M. fulvago sp. nov. falls into the range of variability of M. gigantea regarding these two characters.

The COI sequences group the specimens identified as M. fulvago sp. nov. by morphology into a clade which is supported by a bootstrap of 97%. This clade additionally includes a specimen of M. gigantea. Supposedly this placement is an artefact caused by the short sequence length (261 bp) of this specimen. The maximum intraspecific variation within M. fulvago sp. nov. is 0.8%. Megaxyela togashii is placed at a minimum pairwise distance of 7.6% (Fig. 2).

The specimens from Mount Yunshan were collected on a sunny day flying around birch trees with lots of catkins shedding pollen. Pollen feeding of adults is well known for Xyela species, which bear distally modified and usually extended maxillary palps (Burdick 1961). A similar behavior is unknown for adult Macroxyelinae. Although M. major has been caught from catkins of willow (Bridwell 1906) and pollen has been identified from the intestine of two fossil Macroxyelinae species (Krasilov & Rasnitsyn 1982), Megaxyela is not specialized in pollen feeding but is facultatively palynivorous, because the labiomaxillar complex exhibits no particular modifications for the uptake of pollen as in Xyelinae.

Takeuchi (1940) and Maa (1949) referred to the specimens of M. gigantea collected in “Chinkiang [= Zhenjiang], Prov. Kiangsu [= Jangsu Sheng]” deposited in the collection of the Musée Heude, Shanghai at that time. Major parts of this collection have been incorporated into IZCAS, Beijing (Yang Ganyan, personal communication). The two females and one male collected in “Chinkiang” in 1918 could be identified as M. fulvago sp. nov. with help of photos kindly provided by Yang Ganyan. An additional female from “Chinkian” (3 May 1936, E. Suenson leg.), which we identified as M. gigantea prior to the recognition of M. fulvago sp. nov., is kept at INHS.