Cratotabanus newjerseyensis Grimaldi

Grimaldi, David A., Arillo, Antonio, Cumming, Jeffrey M. & Hauser, Martin, 2011, Brachyceran Diptera (Insecta) in Cretaceous ambers, Part IV, Significant New Orthorrhaphous Taxa, ZooKeys 148, pp. 293-332 : 300-303

Cratotabanus newjerseyensis Grimaldi sp. n. Fig. 4

Diagnosis.

Venation differs from congener by Cratotabanus stenomyomorphus having vein R4 not strongly upcurved (vs. strongly upcurved) and R5 slightly downcurved (vs. nearly in line with R4+5).

Description.

AMNH NJ-1862 (holotype): Body length 1.0 cm, wing length 8.0 mm. Most of left lateral view and some of dorsal, right lateral, and frontal view of face observable. Specimen apparently female. Head: Eyes bare, large, not dichoptic, no differentiation of facets nor apparent color patterns. Details of frons and face not entirely observable (e.g., presence of frontal callus and subcallus unlikely; development of ocelli not discernable). Antenna with scape and pedicel not observable but apparently short (not projected); flagellomere I apically narrowed to 0.5 × basal width, with 3 faint annuli; remaining 6 flagellomeres stylate, tapered apicad, articles of approximately equal lengths [best seen in frontal view]. Proboscis robust, palps barely discernable (but apparently short, length 0.4 × that of proboscis), labellum well developed; entire proboscis fairly long, length = 0.75 × depth of head. Thorax: Standard proportions for Tabanidae ; legs without discernable spurs (although apices of hind tibiae not observable). Metathoracic spiracle also not observable [e.g., presence of postspiracular scale]. Wing: Completely hyaline, no patterning. Base of R2-5 nearly perpendicular to R1, not at a sharp, acute angle. Fork of R4-5 widely divergent and encompassing entire wing tip, base of R4 perpendicular to R5, then strongly and concavely curved to meet C; base of R4 without a small appendix. M1, M2, M3 nearly parallel; M3 and CuA1 convergent (not parallel); CuA1 and A1 meeting just before wing margin. A2 extended nearly to wing margin; alula very large. Abdomen: Details (e.g., segmentation of cerci) not observable.

Specimen. AMNH NJ-1081 (paratype): Thorax + abdomen length 8.2 mm, wing length 8.5 mm (from base of basicosta to wing tip). Wing: Basicosta present as a thick, scale-like lobe at base of vein C. C thickened proximally, circumambient. Short crossvein h present, where costal thickening is narrowed. Sc long, 0.6 × length of wing, straight and parallel to vein C. Veins R and base of R1 also straight, parallel, and close to Sc; apices of Sc and R1 diverging apically. Dark, heavily sclerotized pterostigma covers and surrounds R1, vein C, and extends to tip of R2+3. R2+3 straight, turned slightly upward at apex. Stem of R4 and R5 straight, base of R4 nearly perpendicular to this stem, then curved upward and meeting C anterior to tip of wing; R5 nearly in line with stem of R4+R5. Cell d large, length ca. 2.7 × the width; with veins M1, M2 and M3 each deriving directly from apical wall of cell. M veins slightly divergent, long; M1 slightly longer than cell d, M3 ca. 0.6 × length of cell d. Crossveins r-m and m-cu in line with each other. Veins CuA2 and A1 meet slightly before wing margin, forming long, complete cua cell with very short vein CuA2+A1. Vein A2 well developed, concave to A1, evanescent apically; anal lobe and anal cell well developed. Alula present but partially obscure. Abdomen: Short, broad, tergites short, typical of tabanids.

Types.

Holotype (sex unknown), AMNH NJ-1862, New Jersey (USA): Middlesex Co., Sayreville, White Oaks [Old Crossman’s] pits (Turonian), collected by Stephen Swolensky. Observation of the fly was optimized by embedding the amber in epoxy under vacuum and trimming very close to surfaces of the fly, but the specimen is not well preserved, being occluded with a reddish, crazed layer over most of the body and by similar internal fractures in the piece, as well as by a suspension of fine particles in the amber. Piece is irregular in shape, 10 × 13 mm in largest dimensions. Study of the specimen might benefit from microtomography.

Paratype (sex unknown), AMNH NJ-1081, in Late Cretaceous (Turonian) amber from Crossman’s Pits, Sayreville, New Jersey. Fly is partially preserved: besides the entire right wing and a very small portion of left wing, only the dorsal surfaces of the abdomen and thorax remain; the head and legs are entirely lost. The amber piece is triangular and approximately 19 × 8 × 5 mm, embedded in epoxy but trimmed and polished so as to expose a dorsal view of the fly. The amber itself is light yellow and turbid, with a thick suspension of organic particles that obscures much of the fly. AMNH NJ-1081 differs from NJ-1862 by the following minor venational details: R1 slightly longer, Rs branches from R1 at a more acute angle, proximal end of cell d slightly more shallow V-shaped; A2 slightly shorter. Both specimens are also very similar in body shape and size.

Etymology.

"from New Jersey," in reference to provenance.

Discussion.

These are the only tabanids known to be preserved in Cretaceous amber. Other tabanids in amber are from the Miocene of the Dominican Republic and the Eocene Baltic amber ( Evenhuis 1994).

Ren (1998) described three genera of putative, compression-fossilized tabanids with long proboscides from the Early Cretaceous Yixian Formation of China. Grimaldi (1999) discussed the characters on which his assignment was made, and concluded that these fossils may not be tabanids. For example, features of Palaepangonius eupterus Ren that are inconsistent with Tabanidae are the short, upturned R2+3, very long veins R4 and R5 (half this length and much more divergent in true Tabanidae ), and veins A1 and CuA2 that do not fuse but meet the wing margin independently (Fig. 4c). These do appear to be tabanomorphs, but may be stem-group taxa to Recent Tabanidae , Athericidae , Pelecorhynchidae , and possibly even Rhagionidae (some fossil rhagionids had long, piercing mouthparts). Another early compression fossil, Baissomyia redita , from the Early Cretaceous Zaza Formation of Russia, was attributed to the Tabanidae essentially on the basis of body shape and styletiform mouthparts ( Mostovski et al. 2003), since the antennae and most of the wing (and, thus, most features defining the family) were not preserved. Eotabanoid lordi , from the Early Cretaceous of England, is probably a tabanid, but it too plesiomorphically has long R4 and R5 veins, which are nearly symmetrial (in true tabanids R4 is typically much more curved) ( Mostovski et al. 2003) (Fig. 4c). Besides the specimens in New Jersey amber described herein, the only other definitive Tabanidae from the Cretaceous is Cratotabanus stenomyomorphus from the Aptian-aged Crato limestone of Brazil ( Martins-Neto and Kucera-Santos 1994). Venation of Cratotabanus stenomyomorphus and Cratotabanus newjerseyensis are extremely similar. Another species of the genus from the Crato Formation is as yet undescribed ( Martins-Neto 2003). Diverse Tabanidae occur in Tertiary rocks and amber (summarized by Evenhuis, 1994), but generic assignments of those species described prior to 1950 need to be assessed. Cretaceous fossils assigned to the Tabanidae include the following:

Baissomyia redita Mostovski, Jarzembowski & Coram, 2003: Zaza Formation, Baissa, Transbaikalia, Russia.

Eotabanoid lordi Mostovski, Jarzembowski & Coram, 2003: Durlston Formation (Berriasian), Purbeck Group, Dorset UK.

" Allomyia " [sensu Ren] ruderalis Ren, 1998: Yixian Formation, China.

Eopangonius pletus Ren, 1998: Yixian Formation, China.

Palaepangonius eupterus Ren, 1998: Yixian Formation, China.

Cratotabanus stenomyomorphus Martins-Neto & Santos, 1994: Crato Formation (Aptian), Ceara, Brazil.

" Cratotabanus sp. n.": Crato Formation (Aptian), Ceara, Brazil (in Martins-Neto 2003: pg. 31, ex: Grimaldi 1990).

Cratotabanus newjerseyensis sp.n.: Raritan Formation amber (Turonian), New Jersey, USA (herein).