Bithoracochaeta couriae, Jaume-Schinkel & Ibáñez-Bernal, 2020

Jaume-Schinkel, Santiago & Ibáñez-Bernal, Sergio, 2020, A new species of Bithoracochaeta Stein (Diptera: Muscidae) with comments on Mexican species of the genus and their implication as possible biocontrol agents for greenhouses pests, Zootaxa 4896 (2), pp. 283-291 : 284-287

Bithoracochaeta couriae sp. nov.

( Figs 1–6 )

Diagnosis. Antennae black with silver pollinosity; thorax ground color black with heavy silver pollinosity; mesonotum with five dark vittae, median one broader and reaching suture of scutellum; coxae dark brown with heavy silver pollinosity; fore femur with basal 0.66 thickened and black; mid and hind femora dark yellow in male, dark grey in female; male with cercal plate with anterior margin W-shaped and lateral margin waisted; long, tubular hypandrium with a group of spines laterally.

Description. Holotype male. Head: Coloration: Ocellar tubercle black, surrounded by V-shaped silver pollinosity. Frontal vitta black; fronto-orbital plate black with silver pollinosity; parafacial, facial ridge and face with silver pollinosity; sometimes in lateral view with a frontal light incidence the parafacial seems black with the area just above vibrissa orange; gena and postgena ground color black with heavy silver pollinosity. Scape black with silver pollinosity; pedicel with silver pollinosity; flagellum black with silver pollinosity, arista black. Palpus dark brown, darker towards apex. Proboscis sclerotized, shining black. Distance between eyes at vertex about one third of head width. Chaetotaxy: four pairs of frontal setae, from upper to bottom, first pair parallel, reclinate, second to fourth pairs convergent, third pair about half the length of other pairs. One pair of proclinate long ocellar setae, one pair of smaller divergent setae at disk of the ocellar triangle. Inner vertical setae strong and parallel, outer divergent setae about half the length of inner vertical setae. One pair of divergent postocellar setae, paravertical setae convergent, one line at each side of six occipital strong setae that reaches level of postgena. Antenna inserted just above half of eye height, scape with two marginal setae, pedicel with two pairs of dorsal setae, one short seta on basal half and one longer medial seta, flagellomere lamellate and pubescent, truncated; arista inserted at basal portion of flagellomere, 2.6 the length of the flagellomere, plumose in the hole length. Vibrissa strong, as long as subvibrissal ridge on lateral view, convergent; four subvibrissal setae, about half the length of vibrissa. Facial ridge with two setae above vibrissa. Genal setae black in a single row. Postgenal tuft of black setae. Gena about 0.1 of eye height (in lateral view).

Thorax: Coloration: Ground color black, with heavy silver pollinosity, scutum with 5 dark brown vittae, in dorsolateral view the median one broader and ending at the suture of the scutellum, the dorsocentral vittae ending in the first pair of postsutural dorsocentral setae, and the intra-alar vittae ending on the presutural region. Scutellum and metanotum covered with silver pollinosity. Chaetotaxy: acrostichal setae short, in two rows; dorsocentrals 1:2; intra-alars 1:1; supra-alars 1:2; postalar 1; postpronotal 1; notopleurals 2. Scutellar setae with 2 basal pairs and 1 convergent, not crossed apical pair; basal setae shorter than apical, disk of scutellum with sparse weak setae. Proepisternals 2; proepimerals 2; 5 strong anepisternals on posterior margin and some weak sparse setae; katepisternals 1:2:1 and some sparse short weak setulae; meron bare; katatergite bare; anatergite bare ( Fig. 1 ). Wing: hyaline, yellow veins, R 4+5 and M 1+2 parallel at apex. Calypters white, with white margin and white setae on it, lower calypter almost twice the length of the upper one. Halter general coloration light yellow, with the basal portion brown. Legs: Coxae dark brown with silver pollinosity; trochanter dark yellow; fore femur with the basal 0.66 thickened and black with faint silver pollinosity, the apical 0.33 dark yellow; mid and hind femora dark yellow; fore, mid and hind tibiae dark yellow, tarsomeres slightly darker than tibiae. Fore femur with rows of 5 posterodorsal setae, 6 posterior setae, and 12 posteroventral setae; fore tibia with 2 anteroventral and 1 anterodorsal setae; mid femur with rows of 6 anterior, 8 anteroventral, 6 anterodorsal and 4 posteroventral setae, and 1 preapical setae on each posterior and posterodorsal surfaces; mid tibia with 2 posteroventral, 1 posterior and 1 posterodorsal setae; hind femur with rows of 6 anteroventral, 6 anterodorsal and 1 posterodorsal preapical setae; hind tibia with the characteristic 4 median setae, one on each surface (anteroventral, anterodorsal, posterodorsal and posteroventral), and 1 preapical dorsal, 1 preapical anterodorsal and 1 short stout apical anteroventral setae.

Abdomen: Ground color black, with heavy silver pollinosity, all alveoli of setae surrounded by black coloration; apical margin of tergites dark silver, tergites 1+2–5 with median linear and lateral triangular coppery spots, in some specimens the median spot very diffuse and hard to see. Tergites 1+2–4 with one row of marginal setae stronger and longer than the others, tergite 5 with 3 strong marginal setae at each side; sternite 5 with anterior margin rounded, posterior margin V shaped as in Figure 2

Male terminalia ( Figs 3–6 ): Cercal plate with anterior margin W-shaped, lateral margin waisted at middle, posterior margin with 2 incipient lobes near midline; surstylus with apex hook-shaped posteriorly directed ( Figs. 3–4 ); long, tubular hypandrium, in lateral view with upper and posterior margins strongly concave, lateral surface with a cluster of spines; pregonite with few spines at apex, as shown in Figures 5–6 .

Female. Similar to male, except mid and hind femur with grey coloration in the median portion, all yellow in male, tergites 1+2–5 with median and lateral brown spots smaller than males, females are bigger in body size compared to males.

Type material. Holotype: Mexico, Veracruz, Municipality of Xalapa, Xalapa city, Colonia Ánimas , in a wasteland, 15-XI-2019, 1³ pinned, in good condition, abdomen and terminalia dissected . Paratypes: Same data of holotype, 15-XI-2019, 7³ 10♀ (one male with terminalia dissected); 25-XI-2018, 4♀; 27-XI-2019, 2♀; 27-XI-2018, 1♀; 29-XI-2018, 1³; 27-XI-2019, 1³, 1♀. All specimens deposited in IEXA , except 2³ and 2♀ deposited in CNIN .

Etymology. Name in apposition. The species name is dedicated to Márcia S. Couri for her vastly contributions to the Neotropical Coenosinii and particularly to the genus Bithoracochaeta .

Remarks. As stated by Couri (2005), chaetotaxy of Bithoracochaeta is very homogeneous and species can be differentiated by coloration or by male terminalia. Following the key from Carvalho & Couri (2002) and the description of species of Couri (2005), B. couriae is closely related to B. annulata , B. plumata and B. nigricoxa , but differs as follows.

As B. couriae sp. nov. has black basal flagellomere and arista ciliate in all its length, pedicel grey, outer vertical setae half the length of inner setae, katerpisternals 1:3:1, anepisternum with 5 long setae, all coxae grey, and sternum 5 with basal margin rounded and cercal plate with anterior margin W-shaped and posterior margin with two incipient lobes, differs of B. annulata which has the basal flagellomere yellow and arista with only the basal half ciliate, fore coxa brown with yellow apex, sternum 5 with a pointed projection on basal margin, and cercal plate with posterior margin with no prominent lobes, of B. plumata as it has yellow coxae with brown posterior surface, and cercal plate with anterior margin U-shaped, of B. nigricoxa as it has the apex of pedicel yellow, inner and outer vertical setae similar in length, katerpisternals 1:1:1, and anepisternum with 2 long setae. The body general coloration is very similar in B. nigricoxa and B. couriae sp. nov., including the five vittae on scutum, but in B. couriae sp. nov. the median vittae reaches the suture of scutum-scutellum, while in B. nigricoxa does not. Additionally, B. couriae sp. nov. can be well differentiated from all species by the male terminalia characteristics and the number and disposition of katepisternal setae.

Bithoracochaeta couriae sp. nov. can be differentiated from the other Mexican species as follows: B. leucoprocta lacks the spines on the hypandrium, whereas B. couriae sp. nov. presents spines on the hypandrium; B. calopus presents mid and hind femora at least with brown apices and the hypandrium short, whereas in B. couriae sp. nov. the mid and hind femora are whole yellow and the hypandrium is long. No comparison can be made with Bithoracochaeta pacifera because the type specimens cannot be located and the original description of Giglio-Tos (1893) is not sufficient to distinguish this species.

In the key of Couri & Carvalho (2002), Bithoracochaeta couriae sp. nov. can be included as follows:

7. Male: Flagellomere yellow; fore coxa brown with yellow apex; arista with cilia only on basal two-thirds; katepisternals as in Fig. 114 ( Guyana, Brazil, Peru)........................................................ B. annulata Stein, 1911

- Male: Flagellomere dark with silver pollinosity; arista with cilia in its whole length................................. 8

8. Male: Flagellomere brown with silver pollinosity; fore coxa yellow with the posterior surface brown; katepisternals as in Fig.

113; genitalia as in Motta & Couri (1999) figs. 20, 27, 34............................. B. plumata Albuquerque, 1955 - Male: Flagellomere black with silver pollinosity; all coxae silver; katepisternals as Fig. 1 of the present paper; genitalia as in Figs. 3–6 of this paper................................................................... B. couriae sp. nov.

Figures

FIGURES 1–6. Bithoracochaeta couriae sp. nov. 1. Male, lateral view of thorax showing setae on anepisternum and katepisternum. 2. Male, sternite 5. 3-6. Male terminalia (Holotype). 3. Cercal plate, surstyli and epandrium, dorsal view. 4. Cercal plate, surstyli and epandrium, left lateral view. 5. Aedeagus, dorsal view. 6. Aedeagus, lateral view. Abbreviations: Aede= aedeagus; Anst= anepisternum; Cept= cercal plate; Epan= epandrium; Pregt= pregonite; Hypa= hypandrium; Ktst= katepisternum; Surs= surstylus.