Bactrocera (Asiadacus) connecta Leblanc & Doorenweerd

Leblanc, Luc, Doorenweerd, Camiel, Jose, Michael San, Pham, Hong Thai & Rubinoff, Daniel, 2018, Descriptions of four new species of Bactrocera and new country records highlight the high biodiversity of fruit flies in Vietnam (Diptera, Tephritidae, Dacinae), ZooKeys 797, pp. 87-115 : 95-98

Bactrocera (Asiadacus) connecta Leblanc & Doorenweerd sp. n.

Holotype.

Male. Labelled: "Vietnam: Thừa Thiên–Hu ế Province, Bạch Mã National Park, 16.2098N, 107.8632E, 6-12-x-2015, M. San Jose and D. Rubinoff, FF494, zingerone trap." ms6195 Deposited in UHIM. Paratypes: 3 males. Vietnam, Lâm Đ ồng Province, Cát Tiên National Park, 16-18-x-2015, at the following sites, identified by their geographical coordinates: 11.4485N, 107.4416E, (1 pinned, molecular voucher ms6105), 11.4447N, 107.4372E, (2 pinned, one molecular voucher ms6239). All specimens collected by Michael San Jose and Dan Rubinoff in zingerone baited traps. One paratype deposited at UHIM, one at WFBM and one at VNMN.

Differential diagnosis.

Bactrocera connecta shares morphological features common to all members of Asiadacus (absence of prescutellar and anterior supra-alar setae, scutellum with one pair of setae, and males with long posterior lobe on surstylus, slight concavity of sternum V and pecten of cilia present on the abdominal tergum III). It is distinguished from other members of Asiadacus by the elongate facial spots along antennal furrows and the small to extensive fuscous transverse band on face (Fig. 6A, B), the broad, apically expanded costal band (Figure 6H, I), and the absence of a medial longitudinal band and presence of extensive lateral black markings on the abdomen (Figure 6 D–G).

Molecular diagnostics.

Bactrocera connecta was referred to as Bactrocera species 68, sister to B. (Apodacus) visenda (Hardy), in the seven-gene phylogeny presented in San Jose et al. (2018). The nearest neighbor we could identify based on COI sequence data is Zeugodacus melanofacies , at 15.34 % minimum pairwise intraspecific genetic distance [16.18 % in COI5P and 14.47 % in COI3P] (Figure 5).

Description of adult.

Head (Figure 6A, B). Vertical length 1.64 ± 0.23 (SE) (1.45-1.88) mm. Frons, of even width, length 1.13 ± 0.07 (1.07-1.22) times as long as broad; fulvous with fuscous around orbital setae and on anteromedial hump; latter covered by short red–brown hairs; orbital setae black: one pair of superior and two pairs of inferior fronto-orbital setae present; lunule yellow. Ocellar triangle black. Vertex fuscous. Face fulvous with elongate black spots in each antennal furrow and a fuscous band across lower half of face varying from a small medial spot (Figure 6A) to an entire band across face (Figure 6B); length 0.63 ± 0.09 (0.53-0.75) mm. Genae fulvous, with dark fuscous sub-ocular spot; black seta present. Occiput light to dark fuscous (fulvous laterally in one specimen) and yellow along eye margins; occipital row with 9-11 dark setae. Antennae with segment 1 (scape) fulvous, segments 2 (pedicel) fulvous and fuscous on outer surface, and segment 3 (first flagellomere) fuscous and narrowly fulvous on inner surface; strong red–brown dorsal seta on segment 2; arista black (fulvous basally); length of segments: 0.23 ± 0.02 (0.20-0.25) mm; 0.34 ± 0.02 (0.33-0.38) mm; 0.76 ± 0.07 (0.70-0.83) mm.

Thorax (Figs 6C, 7). Scutum black except sometimes with red–brown as limited markings behind postpronotal lobes and anterior to lateral postsutural vittae and area below postsutural vittae. Pleural areas black except usually red–brown anterior portion of anepisternum. Yellow markings as follows: postpronotal lobes and notopleura (notopleural callus), usually connected by a lateral longitudinal band; medium sized mesopleural (anepisternal) stripe, reaching midway between anterior margin of notopleura and anterior notopleural seta dorsally, continuing to katepisternum as a transverse spot, anterior margin convex; anatergite (posterior apex black); anterior 75 % of katatergite (remainder black); moderately broad medial postsutural vitta beginning at level of or slightly anterior of prescutellar setae and ending at or slightly beyond the level of notopleural suture; two moderately broad parallel sided lateral postsutural vittae ending at or shortly before intra-alar setae and curved inwards along notopleural suture. Postnotum black with apical median red–brown spot. Scutellum yellow except for narrow black basal band. Setae (number of pairs): 1 scutellar; prescutellar absent; 1 intra-alar; 1 posterior supra-alar; anterior supra-alar absent; 1 mesopleural; 2 notopleural; 4 scapular; all setae well developed and red–brown.

Legs (Figure 7). Femora fulvous, except for dark fuscous ventral faces of basal three quarters of fore femur, apical three quarters of mid femur and apical two–fifths of hind femur, and yellow basal quarter of mid femur and basal three–fifths of hind femur; tibiae dark fuscous, with or without ventral faces narrowly fulvous; mid-tibiae each with an apical black spur; tarsi fulvous.

Wings (Figure 6H, I). Length 5.75 ± 0.67 (5.11-6.67) mm; basal costal (bc) and costal (c) cells fuscous and both covered with microtrichia; remainder of wings colorless except broad fuscous costal band nearly confluent with R4+5 and broadly expanded apically; anal streak absent; dense aggregation of microtrichia around A1 + CuA2; supernumerary lobe of medium development.

Abdomen (Figs 6 D–G, 7). Elongate oval; terga free; pecten present on tergum III; posterior lobe of surstylus long; abdominal sternum V with a slight concavity on posterior margin. Tergum I and sterna I and II wider than long. Tergum I black. Tergum II yellow with sub-basal or basal broad medial transverse black band that may be extend ed to cover entire basal half of tergum. Terga III–V black with fulvous areas as small markings on apex of tergum III and narrow median area on tergum IV (or restricted to small apical median marking), continued on base of tergum V and expanded around ceromata. A pair of dark fuscous ceromata (shining spots) on tergum V. Abdominal sterna black, except fulvous sternite II.

Etymology.

The species name is an adjective that refers to the longitudinal yellow band connecting the postpronotal lobes and notopleura.

Note.

We have tentatively assigned B. connecta to Asiadacus based on the following combination of characters: absence of prescutellar and anterior supra-alar setae, scutellum with one pair of setae, a long posterior lobe of the male surstylus, slight concavity of sternum V and pecten of cilia present on the abdomen (Drew 1989, Drew and Romig 2016). All known species of Asiadacus were transferred to Zeugodacus , based on the surstylus and sternum V concavity characters which made them part of the Zeugodacus group of subgenera ( de Meyer et al. 2015). Only more recently was one species, B. (Asiadacus) apicalis , genetically confirmed to belong to Zeugodacus ( San Jose et al. 2018). In that same molecular phylogeny, however, B. connecta is only distantly related to B. apicalis and is placed in the basal grade of subgenera in Bactrocera . Recently, Hancock and Drew (2017, 2018) transferred all but two species of Asiadacus to the subgenera Parasinodacus , Sinodacus and Zeugodacus , leaving in Asiadacus the two species with a large, oval apical wing spot that reaches but does not cross vein M. Because B. connecta falls within Bactrocera in the recently published phylogeny ( San Jose et al. 2018), it cannot be assigned to any of these three subgenera. Moreover, in B. connecta the lateral postsutural vittae are not extended as yellow markings beyond the notopleural suture, a character shared by the Zeugodacus group of subgenera and genus Dacus , referred to as "small notopleural xanthines" by White (2006) and "lateral yellow triangles that reach the notopleural lobes" by Hancock and Drew (2018). Because B. connecta cannot be fitted in existing subgenera and to avoid creating a new subgenus, we arbitrarily assign this species to the subgenus Asiadacus sensu Drew and Romig (2016), until the subgeneric relationships within Bactrocera are more clearly elucidated. It cannot be keyed beyond couplet 4, page 48, in Drew and Romig (2016), where it can be singled out by the costal band on the wing overlapping R2+3 and expanding apically (Figs 6H, I).