Rhaphium canniccii, Grootaert & Taylor & Guénard, 2019

Grootaert, Patrick, Taylor, Christopher & Guénard, Benoit, 2019, Three new species of Rhaphium Meigen, 1803 from mangroves in Hong Kong (Diptera: Dolichopodidae: Rhaphiinae), European Journal of Taxonomy 540, pp. 1-21 : 11-16

Rhaphium canniccii sp. nov.

urn:lsid:zoobank.org:act:273DCEE4-22B1-4048-A32A-912C21B01D1A

Figs 5–6

Diagnosis

Medium-sized species (4.3–4.8 mm long). Legs yellow, but tip of hind femur, base and tip of hind tibia and all hind tarsomeres black. Postpedicel elongate triangular, 1.6–1.7 × as long as wide, arista 1.6–2 × as long as postpedicel. Fore coxa with long bristles, near base with white bristles, on apical half white bristles mixed with black bristles. 4 pairs of acrostichals and 5 dorsocentrals. Fore femur entirely yellow, with short white ventral bristles on basal half. Tip of mid coxa with a number of adhered bristles forming a thorn.

Etymology

The new species is dedicated to Prof. Dr Stefano Cannicci from the Hong Kong University, promoter of the mangrove survey in Hong Kong.

Material examined

Holotype

HONG KONG • ♂; Sheung Pak Nai (10M3); 22.45203° N, 113.96245° E; 14–28 May 2018; C. Taylor and Cheung Shun Chi leg.; RBINS.

Paratypes

HONG KONG • 1 ♂; To Kwa Peng (29M3); 22.42907° N, 114.33326° E, 8–25 May 2018; C. Taylor and Cheung Shun Chi leg.; RBINS • 2 ♀♀; To Kwa Peng (29M4); 22.42804° N, 114.33467° E; 25 May–10 Jun. 2018; C. Taylor and Cheung Shun Chi leg.; HKU • 1 ♀; Yim Tin Tsai (45 AM2 ); 22.37513° N, 114.30168° E, 16 May–1 Jun. 2018; C. Taylor and Cheung Shun Chi leg.; HKU • 1 ♀; Tai O (17 CM1 ); 22.25790° N, 113.86360° E; 20 Oct.–2 Nov. 2017; C. Taylor and U. Chang leg.; RBINS • 1 ♀; Tsim Bei Tsui (Sha Kiu Tsuen) (9EM1); 22.48902° N, 113.99832° E; 31 Oct.–15 Nov. 2017; C. Taylor and U. Chang leg.; muddy back mangrove; RBINS • 1 ♀; Sam A Chung (5 BM1 ); 22.50829° N, 114.27248° E; 11–27 Dec. 2017; C. Taylor and U. Chang leg.; sandy back mangrove; RBINS .

Barcodes

>doli_HKC0000281_Kareen-Nabilah_ INTRN 223_ HongKong _ 31Dec 9999_20180820 female Tai O (the other side) 17 CM 1 GAATAAATGTTGGTAAAGTACTGGATCTCCTCCTCCAGCTGGGTCAAAGAATGATGTATT TAGATTACGATCAGTTAATAATATTGTAATAGCTCCAGCTAAAACAGGTAATGATAATAAT AAAAGAATAGCTGTAATAACTACAGATCATACAAATAATGGTATTCGATCAAGAGTAATTC CTGTTGATCGTATATTAATTACAGTAGTAATAAAATTTACTGCCCCTAAAATAGATGAAATAC CTGCCAAGTGAAGAGAGAAAATAGCCAAGTCAACAGAAGCACCTCCATGGGCAATTCCAG CTGATAAT

>doli_HKC0000914_Nabilah_ INTRN 225_ HongKong _ 31Dec 9999_20180820 female Tsim Bei Tsui (Sha Kiu Tsuen) 9EM1 GAATAAATGTTGGTAAAGTACTGGATCTCCTCCTCCAGCTGGGTCAAAGAATGATGTATT TAGATTACGATCAGTTAATAATATTGTAATCGCTCCAGCTAAAACAGGTAATGATAATAAT AAAAGAATAGCTGTAATAACTACAGATCATACAAATAATGGTATTCGATCAAGAGTAATTC CTGTTGATCGTATATTAATTACAGTAGTAATAAAATTTACTGCCCCTAAAATAGATGAAATAC CTGCCAAGTGAAGAGAGAAAATAGCCAAGTCAACAGAAGCACCTCCATGGGCAATTCCAG CTGATAAT

>doli_HKC0000251_Kareen-Nabilah_ INTRN 223_ HongKong _ 31Dec 9999_20180820 female Sam A Chung 5 BM 1 GAATAAATGTTGGTAAAGTACTGGATCTCCTCCTCCAGCTGGGTCAAAGAATGATGTATT TAGATTACGATCAGTTAATAATATTGTAATAGCTCCAGCTAAAACAGGTAATGATAATAA TAAAAGAATAGCTGTAATAACTACAGATCATACAAATAATGGTATTCGATCAAGAGTAAT TCCTGTTGATCGTATATTAATTACAGTAGTAATAAAATTTACTGCCCCTAAAATAGATGAAAT ACCTGCCAAGTGAAGAGAGAAAATAGCCAAGTCAACAGAAGCACCTCCATGGGCAATTCC AGCTGATAAT

Description

Male

MEASUREMENTS. Body: 4.32–4.48 mm long; wing: 3.52–3.84 mm long.

HEAD. Upper ten postocular bristles short, uniseriate, black; lower postoculars long, white, multiseriate, forming a favoris. Antenna black. Pedicel with a crown of apical bristles, dorsal bristle longer than pedicel. Postpedicel elongate triangular, 1.6–1.7 × as long as wide. Arista 1.6–2 × as long as postpedicel. Palpus black, with black bristles.

THORAX. Shining metallic green. 4 pairs of irregularly set acrostichals, shorter than the five long dc.

WING. Brownish tinged, veins yellowish brown. Squama white, with a fan of long white cilia. LEGS. Yellow with a pattern. Fore coxa exteriorly black on basal half, yellow on apical half. Mid and hind coxae black. Fore femur yellow. Fore and mid tarsomeres 4–5 brown. Apical quarter of hind femur black. Base of hind tibia narrowly black, apical third black. All hind tarsomeres black.

FORE LEG. Fore coxa on basal half covered with long pale hairs and bristles; near base only white bristles, from apical half onward mixed with black bristles. Femur with a ventral row of fine white bristles, half as long as width of femur; four black preapical posterodorsal bristles, as long as depth of femur; a row of posterior black bristles over entire length, as long as width of femur. Tibia with three dorsal bristles, basalmost half as long as second and third bristle; no apical crown of bristles.

MID LEG. Coxa without exterior bristles but anteriorly densely set with black bristles, mixed with a few fine pale bristles; tip with a number of adhered bristles forming a thorn (spur). Femur without ventrals; two fine anterior preapicals; two longer posterior preapicals. Tibia with three anterodorsal and three posterodorsal bristles; an apical crown of strong bristles.

HIND LEG. Coxa with a few pale anterior hairs and two stronger black exterior bristles just above tip (a long upper and a short lower bristle). Femur with a strong anterior preapical and a shorter posterior preapical; a short row of anteroventral preapicals; no ventrals. Tibia with three anterodorsals and three posterodorsal bristles, a crown of strong apicals.

ABDOMEN. Shining metallic green. First tergite set with long pale hairs at sides and some black marginals. Tergites 2 and 3 dorsally with short black bristles and long pale bristles at sides.

MALE TERMINALIA ( Fig. 6 ). Cercus very long, nearly twice as long as genital capsule ( Fig. 6C ), wide on basal third. Tip of hypandrium pointing up ventrally and with a clockwise twist. Surstyli rounded in lateral view ( Fig. 6D ).

Female

MEASUREMENTS. Body: 4.5–4.6 mm long; wing: 3.8 mm long.

HEAD. Antenna: scape: 0.09 mm; pedicel: 0.065 mm; postpedicel: 0.13 mm; arista: 0.52 mm. Postpedicel triangular, 1.5 × as long as wide. Arista 4 × as long as postpedicel.

FORE COXA. Entirely yellow, anteriorly set with long white bristles, only the apical bristles black. Mid coxa anteriorly with long, fine white bristles mixed with a few black bristles; apex with a few black

bristles, not forming a spur as in male. Sides of tergites 1, 2 and 3 also with white bristles, but shorter than in male. Wing darker brownish tinged than in male.

Remarks

There is a sexual dimorphism in this species in the colour of the fore coxa, which is almost entirely black on the basal half in the male but entirely yellow in the female. This is also the case in the female of Rhaphium mediocre ( Becker, 1922) and R. eburnea ( Parent, 1926) , to which R. canniccii sp. nov. is closely related.

Rhaphium eburnea has been considered to be a junior synonym of R. mediocre ( Negrobov 1979; Yang et al. 2011). However, examination of the type material of the two species supports their recognition as distinct. Becker (1922) described the postpedicel in R. mediocre as twice as long as wide and the arista as equally long. A photo of the lectotype male shows that the arista is at most 1.2 × as long as the postpedicel ( Fig. 7 ). Parent (1926) described the postpedicel in R. eburnea as being twice as long as wide, and the arista as about 1.5× as long as the postpedicel. However, in the lectotype male the arista is 3 × as long as the postpedicel ( Fig. 8 ). In R. canniccii sp. nov., the postpedicel is shorter than in both other species, 1.6–1.7 × as long as wide, with the arista 1.6–2 × as long as the postpedicel. In the redescription of R. mediocre given by Yang et al. (2011: fig. 806) the arista is described as 2 × as long as the postpedicel. This was based on new material collected in Shanghai and not on the type material of either of the two species. Hence, it is not unlikely that another, yet undescribed species is involved.

Negrobov (1979: fig. 1817) illustrated the male terminalia of R. mediocre based on the lectotype and that figure was copied in Yang et al. (2011: fig. 806c). The tip of the hypandrium turns counter-clockwise in R. mediocre but clockwise in R. canniccii sp. nov. ( Fig. 6 ). In R. mediocre , the fore coxa is covered with black bristles ( Fig. 9 ) and the basal segment of the arista is shorter than in R. canniccii sp. nov. ( Fig. 7 and Fig. 5 , respectively).

As yet, only a small number of species groups have been recognised within Rhaphium and that on the basis of selected unusual characters, with the majority of species as yet unplaced in species groups ( Tang et al. 2016). An extensive revision of relationships within this large and complex genus is beyond the scope of the present paper. Nevertheless, a group of species related to Rhaphium micans (Meigen, 1824) may be recognised as having a postpedicel (first flagellomere) at most 2.5 × as long as wide with a longer arista (1.2 to 3 × as long as the postpedicel), 5 dc, long flattened cerci (nearly twice as long as epandrium), short surstyli that are rounded in lateral view and a twisted erect hypandrium. Members of this group include R. bisectum Tang et al., 2016 , R.cannicii sp. nov., R. dispar Coquillet, 1898 , R. eburnea , R. gansuanum Yang, 1998 , R. lumbricus Wei, 2006 , R. mediocre , R. micans , R. tianshuiense Qilomoge et al., 2019 and R. wuduanum Wang et al., 2005 .

Figures

Fig. 5. Rhaphium canniccii sp. nov., holotype, ♂, habitus (RBINS). Scale bar: 1 mm. (Photo credit Ms Camille Locatelli)

Fig. 6. Rhaphium canniccii sp. nov., holotype, ♂, terminalia (RBINS). A. Surstylus, lateral view. B. Epandrium, ventral view. C. Epandrium with cerci ventral view. D. Epandrium, lateral view. Abbreviation: hy = hypandrium. Scale bars: 0.1 mm.

Fig. 7. Rhaphium mediocre (Becker, 1922), lectotype, ♂, head in lateral view (coll. mfn-berlin). (Photo credit Mr Bernhard Schurian and Sven Marotske)

Fig. 8. Rhaphium eburnea (Parent, 1926), lectotype, ♂, habitus (MNHN). (Photo credit Mr Emmanuel Delfosse, MNHN)

Fig. 9. Rhaphium mediocre (Becker, 1922), lectotype, ♂, habitus, with labels and preparation of male terminalia on plastic sheet (MfN). (Photo credit Mr Bernhard Schurian and Sven Marotske)