Leptomorphus, : Edwards, 1925

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 74-76

Monophyly of Leptomorphus

The phylogenetic analysis based on 35 ingroup taxa and 4 outgroups ( Table 2) resulted in three equally parsimonious trees (length = 259, C.I. = 0.40, R.I. = 0.80). Tree support values (Bremer (Br) and bootstrap>50%) are shown on the branches of the strict consensus tree ( Fig. 150). One of the three equally parsimonious trees was selected for discussions of species relationships, classification, and character evolution within the genus. Character state changes are shown on the branches of this tree ( Figs. 151–155).

The monophyly of Leptomorphus is supported (Br = 4, Fig. 150) by two uniquely-derived synapomorphies ( Fig. 151): scape with apicoventral process present (character 2: state 1, hereafter e.g. 2:1), and wing vein C ending at R 5 (40:1), and by three homoplasious character states: head yellow (1:2), very few, fine bristles on face (9:1), and scutellum yellow (23:1).

Leptomorphus perplexus came out as the sister group to the rest of the genus ( Figs. 150, 151); however, this species is only known from the female, so no male genitalic characters were included in the analysis. If and when males are found additional genitalic characters may change the arrangement within the remaining species. Although L. perplexus seems to share a number of characters with the L. walkeri group it does exhibit a large number of plesiomorphic character states, so would likely retain its basal position. The remaining species form a clade, supported by three uniquely-derived synapomorphies (Br = 5, bootstrap = 67): inter-ommatidial setulae only present in ~1/4 of junctions (15:1), ocelli closely associated, forming an ocellar triangle with a dark background (18:1), and acrostichal setae absent (21:1). Eleven homoplasious character states also support this clade: scape setae in single apical row extending from dorsum laterally into thick patch covering apicoventral process, basal third and entire medial surface bare (3:1), inter-antennal bristles on frons few, short, often difficult to see (11:1), space between ocelli less than diameter of lateral ocelli (16:1), lateral ocellus between 1.5 and 3X own diameter from eye margin (17:2), foreleg first tarsomere length>1.5X tibia length (31:2), R 4 absent (41:1), sternite 9 not more than 2/3 the width of tergite 9 (46:1), sternite 9 with anterior margin convex or flat (47:1), tergite 9 with posterolateral lobes (evaginations) present (49:1), posterior margin of tergite 9 with two lobes (50:2), and tergite 9 with posterolateral lobes (evaginations) broad for at least half of length, rounded or square apically (sometimes with multiple points) (51:1).

The remaining species fall into four monophyletic species groups ( Fig. 151); the L. ornatus group (7 spp., Fig. 152), L. grjebinei group (10 spp., Fig. 153), L. walkeri group (10 spp., Fig. 154), and L. furcatus group (9 spp., Fig. 155). The L. ornatus and L. grjebinei groups form a monophyletic clade supported by two uniquely-derived synapomorphies (Br = 4, bootstrap = 62): tergite 9 and gonocoxite margins at least partially fused but discernible as a crease (54:1), gonostylus bare (64:1), and by six homoplasious character states: clypeus dorsoventrally elongate oval or square (6:2), clypeus with 2–8 strong bristles only along ventral margin (8:1), palp segment 5 with central portion thinner than apex and base (13:1), dorsocentral setae present as single or double line of fine setae, usually spaced ~their own length apart (22:1), bristles on tergite 8 restricted to apicolateral corners (45:1), and gonocoxite III fused to gonostylus (65:1).

The L. walkeri and L. furcatus groups also form a clade supported by one uniquely-derived synapomorphy (Br = 4): gonocoxite placed distally or apically on tergite 9 (55:1), and four homoplasious character states: male foretibial comb of bristles present (30:1), tergite 8 bare (45:2), aedeagus initially tapered but ending in sclerotized apex with one or more lateral lobes/flanges of various lengths and ornamentation (66:2), and paramere a curved taper (71:1).