Anthrax succini Greenwalt and Evenhuis

Greenwalt, Dale E., Wingerath, Jonathan G. & Evenhuis, Neal L., 2015, Two new and disparate fossil bee flies (Bombyliidae: Anthracinae) from the Americas and reassessment of Anthrax dentoni Lewis, 1969, Palaeontologia Electronica 24 (1), pp. 1-10 : 3-6

Anthrax succini Greenwalt and Evenhuis , new species

( Figures 1-3 )

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Etymology. The specific epithet derives from the Latin succinum meaning amber.

Holotype. USNM 508762 ; deposited in the Department of Paleobiology, National Museum of Natural History ( NMNH), Smithsonian Institution , Washington, District of Columbia.

Type Horizon. Dominican amber, Miocene.

Type Locality. NMNH’s Brodzinsky Lopez-Pena collection of Dominican amber.

GREENWALT, ET AL.: TWO NEW FOSSIL BEE FLIES

Differential Diagnosis. In the key of Marston (1970), this specimen keys to the cephus group based on the solid pigmentation of its wings and the presence of facial setae extending almost to the antennae. The lack of cross-veins in cells m 2 and r 2+3, alula with a straight posterior margin, cell cup more than half pigmented, pigment in cell r 1 extending to wing apex, and middle femur with postmedial bristles anteriorly, keys this species to Anthrax delicatulus Walker, 1849 . Both the female and male of A. delicatulus differ from related species in having postmedial bristles anteriorly on the middle femur. Females of A. delicatulus have been reported from Jamaica while a male has been reported from the Dominican Republic ( Marston, 1970). Anthrax succini differs from the female of A. delicatulus in the form of veins R 4 and M 1, the relative positions of the distal portions of A 1 and CuA 2 and the length of the styliform portion of the first flagellomere relative to that of the second flagellomere.

Description. Female. Lengths: Body (base of scape to end of the extended sand chamber at the terminus of the abdomen): 8.45 mm ( Figure 1 ); wing (edge of thorax to apex): 9.37 mm with a maximum width of 2.54 mm.

Head. Face, gena, front, vertex, and occiput all dark brown; eyes light brown with pronounced posterior indentation and short line bisecting the facets; vertex covered with short dark brown setae ( Figure 1 , 2 ). Face not tumid, upper half covered with dark brown setae to base of antennae, setae shorter medially and closer to scape, longer but thin laterally and longer and more stout anteriorly. All antennal segments dark brown, completely covered with short whitish microtrichia, especially pronounced at basal and apical perimeters of scape. Scape angled medially with dark setae basally ( Figure 2 ). Pedicel with fewer and shorter setae. First flagellomere onion shaped, subconical basally, with elongate subcylindrical apical portion, cylindrical portion equal in length to the subconical base; second flagellomere subcylindrical, approximately 1/4 as long as the elongate apical portion of first flagellomere; style whitish; apex surrounded by several setae ( Figure 2 ). Ocellar tubercle minute; posteroventral margin of occiput with fringe of short white setae. Mouthparts not present in specimen (not preserved).

Thorax. Anterior edge of mesonotum and pleura with collar of long white setae that surround the occiput of the head ( Figure 3 ); mesonotum with very long stout black macrochaetae laterally, two anterior and three posterior of wing base; mesonotum and scutellum dark brown, sparsely covered with short fine brown setae dorsally, with long white setae laterally; all lateral and medial sclerites dark brown; mesosternum bare except for short white setae along its posterior edge; mesopleuron with white setae over its posterior 2/3 with the setae becoming longer more posteriorly with a single long black macroseta originating posterior to anepisternal suture; anepimeron, meron, laterotergite, and metepimeron bare. Halter slightly recurved, knob light brown, base with setae at anterior edge.

Legs.Procoxa with brown setae and sparse white scales, mesocoxa with black setae; meso and metafemora with basal white scales. Anterior side of mesofemora with three stout bristles posteromedially. Tibia (partially) and tarsi (completely) missing on all legs.

Wing ( Figure 3 ). Hyaline except for brown pigmentation anteriorly and basally. Basicosta stout, triangular, slightly recurved posteriorly, ending in sharp point. Cells c, sc, r 1, bm, and bm and all of r 2+3 except for its posterior-most edge along R 4 pigmented, as well as basal half of cell r 5, anterobasal quarter of discal cell and basal half of cell cup; r-m cross-vein at basal third of discal cell (cell 1m 2) and just distal of origin of R 2+3; veins in radial field without recurrent spurs. M 1 and M 2 terminate at wing margin; length of contact between cells 1m 2 and cua 1 twice that of base of cua 1; cell cup present, terminating just over a third of the way along CuA 2; A 1 terminating at margin basal of CuA 2; anal lobe as wide as cup, margin not reduced. Alula small, slightly convex distally, but recurved and narrow and straight basally.

Abdomen. Tergites covered with short black setae except tergite 2 covered by short white setae form-

GREENWALT, ET AL.: TWO NEW FOSSIL BEE FLIES ing a conspicuous transverse band; tergite 2 with dense patch of long, stout white setae laterally. Medial portion of sternites 1-3 covered with fine short white setae which are also found laterally. Short white setae continue, albeit less thickly, posteriorly along the lateral edges of sternites; posterior sternites covered with longer fine black setae medially and laterally. Apex of abdomen with exserted sand chamber filled with fine sand grains. Type material. Holotype female ( Figure 1 ): Dominican amber, USNM # 508762 . Synclusions include a single nematoceran fly, a very small (<1 mm) adult psocopteran and what appears to be a second specimen of A. succini . However, the entire head of the latter insect is missing and most of the remaining morphological details are obscured due to opaque amber.

Figures

FIGURE 1. Anthrax succini sp. nov., USNM # 508762. Scale bar equals 2 mm.

FIGURE 2. Antennae of Anthrax succini sp. nov., USNM # 508762. Inset = magnified image of the stylet of the right antenna. Scale bar equals 250 Pm.

FIGURE 3. Anthrax succini sp. nov., USNM # 508762. 1. Vestiture from ventral aspect of the specimen. Arrows, from left to right, denote the bare anepimeron and the band of white setae across the anterior sterna of the abdomen; 2. Left wing. The arrow points to the basicosta. Scale bars in both figures equal 1 mm.