IDIOLABIS Alexander, 1931

Kania, I & Krzemiński, W-, 2015, A new species of Dactylolabis (Idiolabis) Alexander, 1931 from the Eocene Baltic amber and its relationships among Dactylolabinae (Diptera: Limoniidae), Palaeontologia Electronica 49 (2), pp. 1-15 : 4-10

Subgenus IDIOLABIS Alexander, 1931

Type species. Dactylolabis (Idiolabis) terebrella Alexander, 1931

Species Dactylolabis (Idiolabis) ryszardi n. sp.

Figures 1 , 2 , 3

zoobank.org/ 107A6239-9A4A-49AE-A24E-0108DC43FBDE

Type material. Holotype: No. MP/3321 (male) Institute of Systematic and Evolution of Animals, Polish Academy of Sciences ( ISEA PAS).

KANIA & KRZEMIŃSKI: EOCENE CRANE FLY FROM BALTIC AMBER

Derivatio nominis. The specific name is dedicated to Prof. Ryszard Szadziewski, eminent specialist on fossil and recent Diptera .

Diagnosis. Vein Sc ending before the fork of Rs into R 2+3+4 and R 5; discal cell comparatively small, characteristically indented in upper distal corner by the position of dM 1+2 shifted to 1/3 of d cell. Cross-vein m-cu before fork of Mb into M 1+2 and M 3+4. Tergite IX without process, indented in the middle. Gonocoxite elongated, narrow basally; gonostyle very elongated, very tiny with short, wide, distinctly crenate process at base.

Description. The male specimen is almost entirely preserved, with wings not well preserved, very dis-

PALAEO- ELECTRONICA.ORG torted ( Figure 2.1 ). Body brown, 7.30 mm long; wing length 9.76 mm; antenna 3.02 mm long.

Head: antenna ( Figures 1.3 , 2.2 ) 16-segmented, if bent backwards, it would reach the base of abdomen; scape long, cylindrical; pedicel not very elongated, rather cylindrical; flagellomeres elongated with several, usually four, setae (verticils) on each flagellomere equal or longer than the segments bearing them; apical flagellomere approximately half as long as penultimate one and widened in distal part with four elongated setae at apex; palpus ( Figures 1.2 , 3.1 ) 0.88 mm long, with the last segment as long as the penultimate one.

Wing ( Figure 1.4, 1.5 ): slightly brown infuscate, vein Sc ending before the fork of Rs into R 2+3+4 and R 5; cross-vein sc-r at twice its length before the end of Sc; R 1 very long; Rs comparatively long; discal cell comparatively small, characteristically indented in upper distal corner by the position of dM 1+2 shifted to 1/3 of d cell; cross-vein m-cu before fork of Mb into M 1+2 and M 3+4; M 1 long, about two times dM 1+2; M 3 slightly longer than discal cell.

Hypopygium ( Figures 1.1 , 3.2 ): 1.10 mm long, tergite IX without process, indented in the middle. Gonocoxite elongated, narrowed basally. Gonostylus very thin, strongly elongated, with short basal process, wide, distinct denticles at margin. Aedeagus protruding; parameres shorter than aedeagus.

Phylogenetic Analysis

The parsimony analysis yielded four trees 41 steps long, with consistency index 0.60, and retention index 0.75. The strict consensus tree ( Figure 4 ) and majority rule ( Figure 5 ) present similar topologies, with a difference in resolution of extinct species Dactylolabis amberifiis + Dactylolabis viduus – not resolved in strict consensus (Nelsen) tree, but resolved in Majority Rule tree. The strict consensus tree revealed two main clades – clade B: [ Bothrophorus monstrosa + Coenolabis aberrans + Dactylolabis montana Eudactylolabis damula ] comprising representatives of extant subgenera and second clade – clade C, comprising species of extinct subgenera with exception of above mentioned two fossils from Baltic amber, placed originally in nominative subgenus Dactylolabis , but with relationships unresolved by the present analysis. Majority rule (cut off at 50) tree presents three clades, clade A: [ Dactylolabis amberifiis + Dactylolabis viduus ] supported by homoplasy, very light stigma, present also in clade comprising species of the genus Eolabis . Separation of this group from modern Dactylolabis montana could be due to missing data for the fossils. Clade B is partly solved: [ Coenolabis aberrans + Dactylolabis montana + [ Bothrophorus monstrosa + Eudactylolabis damula ]] and supported by two synapomorphies – compound eyes occupying more than half of lateral surface of head and presence of two tibial spurs. In the strict consensus tree clade B is supported by in addition by homoplastic feature – enlarged thorax.

Clade [ Bothrophorus monstrosa + Eudactylolabis damula ] in the majority rule tree is supported by homoplasy, not produced gonocoxite, shared with majority of known fossils from Baltic amber.

Clade C presents the same topology in both trees, with species grouped in genera as recently recognized. Aurolabis labis and Eolabis artis share two homoplasies, i.e., reduction of crossvein m-m and absence of separate vein M 2, the latter present also in Eolabis ambustus . Clade grouping species of the genus Idiolabis , i.e., [ Idiolabis terebrella + [ Idiolabis christelae + Idiolabis ryszardi ]] is present insingle synapomorphy, strong elongation of male genitalia, and two symplesiomorphies, thorax not enlarged and tergite IX and gonostylus without additional complications in structure. A single synapomorphy, gonostylus with basal lobe short, hardly reaching 1/3 of the gonostylus length supports [ Idiolabis christelae + Idiolabis ryszardi ]. The clade grouping majority of Eolabis species, i.e., [ Eolabis latusta + [ Eolabis ambustus + Eolabis vetusta + Eolabis vyshniauskasi ]] is not supported by synapomorphy, but with two homoplasies. [ Eolabis ambustus + Eolabis vetusta + Eolabis vyshniauskasi ] is supported by homoplastic feature, tip of A 2 at the level of Rs base, shared with Limnophila pictipennis and Dactylolabis amberifis . The last clade, comprising species of the genus Eobothrophorus is supported by single synapomorphy, enlarged and compressed male genitalia, and homoplasy, IXth tergum with median lobe. Relationships within this clade remain unsolved.

Figures

FIGURE 1. Dactylolabis (Idiolabis) ryszardi sp. nov., No. MP/3321 (male), holotype (ISEA PAS). 1, hypopygium (dorsal view); 2, palpus; 3, antenna; 4-5, wing venation; 4, well visible part of wing; 5, recontruction. Abbreviation of male hypopygium: gx – gonocoxite, gn – gonostylus, aed – aedeagus, p – paramere.

FIGURE 2. Dactylolabis (Idiolabis) ryszardi sp. nov., No. MP/3321 (male), holotype (ISEA PAS). 1, the body, latero- ventral view; 2, head and thorax with appendages.

FIGURE 3. Dactylolabis (Idiolabis) ryszardi sp. nov., No. MP/3321 (male), holotype (ISEA PAS). 1, head with palpi and basal segments of antennae; 2, hypopygium, dorsal view.

FIGURE 4. Preferred relationships tree of subgenera of the genus Dactylolabis. Filled circles indicate synapomorphies or autapomorphies; open circles indicate plesiomorphies. Extant taxa marked in grey, extinct taxa marked in black, new species noted in dark grey. Number of character above the circles, state of character below the circles. Range of clades marked in gray boxes on the right. Bootstrap values are given at the nodes.

FIGURE 5. Strict consensus tree of subgenera of the genus Dactylolabis. Filled circles indicate synapomorphies or autapomorphies; open circles indicate homoplasies or plesiomorphies. Extant taxa marked in grey, extinct taxa marked in black, new species noted in dark grey. Number of characterabove the circles, state of character below the circles. Range of clades marked in gray boxes on the right. Bootstrap values are given at the nodes.