Procladius enigmaticus, Published, 2007

Published, First, 2007, Chironomid midges from early Eocene amber of France (Diptera: Chironomidae), Zootaxa 1404, pp. 1-66 : 15-19

Procladius enigmaticus n. sp.

( Figs. 10 –12)

Etymology: We name this fossil species for its uncertain affinities.

Diagnosis: MCu basal to FCu; distance between them only slightly shorter than Cu 1; wing with few macrotrichia; comb of hind tibia with 1 row of bristles; gonostylus not sharply hooked and with small but distinct heel; superior volsella elongate.

Description: Head deformed, 0.3 mm long; ocelli absent; antenna 0.74 mm long, much longer than head, distinctly hairy, with 14 flagellomeres, all covered with long setae (shortest 0.01 mm long, longest 0.4 mm long), pedicel broad and short, rounded, 13 th flagellomere longest, 0.39 mm long; 14 th flagellomere with apical nipple but without subapical setae; eye bare but deformed, with strong parallel­sided dorsomedial extension, with 4 rows of ommatidia at minimum width; mouthparts lacking functional mandibles; 5 palpomeres with numerous setae and all cylindrical; postocular and inner and outer vertical setae present, frontal setae absent.

Thorax 0.8 mm long, 0.44 mm wide, 0.76 mm high; postnotum bare, with 1 longitudinal median groove; surface of scutellum with numerous and multiserial long setae; scutal tubercle absent; 1 supraalar setae, 4 prealar setae; numerous short and biserial anterior acrostichals; few short and uniserial dorsocentrals; preepisternal setae absent. Wing macropterous, 1.3 mm long, 0.34 mm wide, hyaline, with few macrotrichia present at tip of wing; anal vein An 2 absent; radius with 3 branches R 1, R 2+3, and R 4+5; R 2+3 well separated from R 1 and nearly to R 4+5, R 2+3 apically forked into R 2 and R 3; R 2 0.02 mm long, ending in R 1, R 3 0.19 mm long, ending in costa; costa ending just beyond insertion of last branch of radius, produced by 0.07 mm, more than length of cross­vein RM; only M 1+2 and M 3+4 present; cross­vein MCu present; cubital fork 0.11 mm distal to and beyond cross­vein MCu, cross­vein RM 0.05 mm proximal to MCu; anal lobe well developed; squama fringed. Halter 0.2 mm long. Fore femur 0.52 mm long, tibia 0.61 mm long, tarsus 1.15 mm long; mid femur 0.67 mm long, tibia 0.57 mm long, tarsus 0.82 mm long, hind femur 0.5 mm long, tibia 0.65 mm long, tarsus 0.9 mm long; all tibial spurs with lateral teeth, distal tooth on outer tibial spur rather long, comb­like, those of hind legs not flattened, 2 tibial spurs on hind leg; 4 th tarsomeres of all legs cylindrical, not cordiform; a hind tibial comb of 1 row, pulvilli absent. Abdomen 1.72 mm long, 0.28 mm wide; gonostylus with short setae, elongate, 0.08 mm long, 0.02 mm wide at base, with short posterior heel; gonocoxite 0.14 mm long, 0.09 mm wide at base, numerous long setae on outer surface of gonocoxites; anal point conical and broad, 0.1 mm wide at base, 0.06 mm long; superior volsella elongate.

Discussion: In the key to dipteran families of McAlpine (1981), Procladius enigmaticus n. sp. falls in the Tanypodinae . In the key to Nearctic tanypodine tribes and genera of Oliver (1981) and Fittkau (1962) and the key to Holarctic genera of Murray & Fittkau (1989), P. enigmaticus falls in the Procladiini . Procladius enigmaticus would fall near the recent genus Procladius , based on a gonostylus not sharply hooked and with a small but distinct heel. This last character would exclude affinities with Djalmabatista and support its placement as Procladius subgenus Holotanypus , but the differences between the two genera are few and ambiguous. The elongate superior volsella is another character supporting the placement of P. enigmaticus in this latter subgenus. Procladius and Djalmabatista are widespread, and Holotanypus is known in the Holartic, Oriental, and Afrotropical regions.

Material: Holotype PA 5502, paratypes PA 7945 and PA 8127, all males.

FIGURE 11. Procladius enigmaticus n. sp., holotype PA 5502, photograph of male genitalia.

FIGURE 12. Procladius enigmaticus n. sp., holotype PA 5502, drawing of male genitalia (scale bar = 0.1 mm).

Tribe Coelotanypodini FITTKAU, 1962 (see Spies 2005)

Genus Coelotanypus Kieffer, 1913

Coelotanypus electronicus n. sp.

( Figs. 13, 14)

Etymology: This species is named after elektron, the Greek name for amber.

Diagnosis: Eyes with wide dorsomedial extension; apical nipple on terminal flagellomere; small scutal tubercle with numerous setae present; 1 seta on posnotum; wing without macrotrichia; R 2 incomplete, not joining R 3; MCu at level of FCu; ta4 cordiform and shorter than ta5; comb on hind tibia double; setae on gonocoxite present.

Description: Male head deformed, 0.64 mm long; ocelli absent; antenna 0.96 mm long, much longer than head, distinctly hairy, with 14 flagellomeres covered with long setae (shortest 0.04 mm long, longest 0.46 mm long), pedicel broad and short, 13 th flagellomere very long, 0.51 mm long, 14 th with distinct apical nipple; eye bare but deformed, with apically expanded dorsomedial extension, with 4 rows of ommatidia at minimum width; all palpomeres with numerous setae, no frontal setae, numerous postocular and inner vertical and outer vertical setae. Thorax 1.04 mm long, 0.5 mm wide; 1 long seta on postnotum, with longitudinal median groove; 2 setae on surface of scutellum; small scutal tubercle with numerous setae (distinctly visible on paratype PA 6575); 1 supraalar seta; 5 prealar setae; anterior acrostichals and dorsocentrals absent; postanepisternals not visible. Wing macropterous, 1.74 mm long, 0.5 mm wide, hyaline, without macrotrichia, covered with microtrichia; anal vein An 2 absent; radius with 2 branches R 1 and R 4+5, R 2+3 absent but R 2 incomplete, not joining R 3 present on R 1; costa ending just beyond insertion of last branch of radius, produced by 0.05 mm, less than length of cross­vein RM, ending almost at M 1+2; only M 1+2 and M present; cross­vein MCu present; cubital fork rather distal to and beyond cross­vein MCu; MCu before cubital fork; cross­vein RM 0.08 mm long. Halter 0.27 mm long. Fore tibia 0.94 mm long, tarsus 1.28 mm long; mid femur 0.88 mm long, tibia 0.74 mm long, tarsus 0.94 mm long; hind tibia 0.82 mm long, tarsus 1.06 mm long; all tibial spurs with lateral teeth, comb­like; 2 hind leg tibial spurs, respectively 0.04 mm long and 0.03 mm long; ta4 cordiform and shorter than ta5; hind tibial comb of 2 rows (distinctly visible on the paratype PA 171); mid and hind legs with 2 pseudospurs on the ta1, ta2 and ta3. Abdomen 1.9 mm long, 0.36 mm wide; gonostylus nearly bare, strongly curved, 0.09 mm long, 0.008 mm wide, with strong megasetae apically, distinctly shorter than gonocoxite 0.15 mm long, 0.09 mm wide, gonocoxite with long setae; anal point broad and conical (0.1 mm wide at base, 0.05 mm long).

3+4

Female head deformed, 0.53 mm long; ocelli absent; antenna 0.57 mm long, longer than head, with 13 flagellomeres covered with short setae, pedicel narrow and short, 13 th flagellomere much longer, 0.13 mm long and with distinct apical nipple and apical setae; eye bare, with apically expanded dorsomedial exptention, with 3 rows of ommatidia at minimum width; all palpomeres with numerous setae, no frontal setae, numerous postocular and inner vertical and outer vertical setae. Thorax with small scutal tubercle with numerous setae; preepisternum bare. Wing macropterous, 1.7 mm long, 0.5 mm wide, hyaline, without macrotrichia, covered with microtrichia; anal vein An 2 absent; radius with 2 branches R 1 and R 4+5, R 2+3 absent but R 2, 0.06 mm long, incomplete, not joining R 3, present on R 1; costa ending just beyond insertion of last branch of radius, produced by 0.07 mm, less than length of cross­vein RM, ending almost at M 1+2; only M 1+2 and M 3+4 present; cross­vein MCu present; cubital fork proximal to and beyond cross­vein MCu; MCu before cubital fork; cross­vein RM 0.09 mm long. Halter 0.17 mm long. Fore femur 0.7 mm long, tibia 0.72 mm long, tarsus 1.1 mm long; mid femur 0.72 mm long, tibia 0.78 mm long, tarsus 0.9 mm long; hind femur 0.68 mm long, tibia 0.84 mm long, tarsus 1.06 mm long; all tibial spurs with lateral teeth, comb­like; 2 hind leg tibial spurs, 0.05 mm long; ta4 cordiform and shorter than ta5; hind tibial comb of 2 rows, mid and hind legs with 2 pseudospurs on the ta1, ta2 and ta3.

FIGURE 14. Coelotanypus electronicus n. sp., holotype PA 2347, drawing of habitus (scale bar = 1 mm), drawing of male genitalia (scale bar = 0.1 mm).

Discussion: In the key to dipteran families of McAlpine (1981), this fossil falls in the family Tanypodinae . In the key to Nearctic tanypodine tribes and genera of Oliver (1981) and Fittkau (1962) and the key to Holarctic genera of Murray & Fittkau (1989), C. electronicus falls in the Coelotanypodini (two genera Clinotanypus Kieffer, 1913 , and Coelotanypus Kieffer, 1913 ) because of the following characters: ta4 cordiform and shorter than ta5; comb on hind tibia double; wing without macrotrichia; and R 2 incomplete, not joining R 3.

The terminal flagellomere with an apical nipple, MCu at the level of FCu, and a small scutal tubercle bearing numerous setae support affinities of our specimens with the genus Coelotanypus versus Clinotanypus . These characters, valid for the Holarctic species, are more uncertain at a world scale; however, the African Clinotanypus maculatus Freeman, 1955 , has a small scutal tubercle ( Freeman 1955), and MCu at the level of FCu in our fossils excludes affinities with Clinotanypus . Conversely, the presence of one postnotal seta in our specimens is characteristic of the genus Clinotanypus . The eye with a wide dorsomedial extension, posnotum setose, MCu almost at FCu, and the presence of setae on the gonocoxite exclude the genus Naelotanypus Roback, 1982 ( Roback 1982: figs. 1, 2). Because it has the main diagnostic characters of Coelotanypus , we include our fossils in this genus. It can be separated from the recent species by the presence of one postnotal seta.

Material: Holotype PA 2347, males paratypes PA 10550, PA 9761, PA 12663, PA 6575, PA 454, PA 15030, PA 1182, PA 5997, PA 2709, PA 8177, PA 6469 and PA 171 2/2, females paratypes PA 3798, PA 4246, PA 2871 and PA 2752.