Paramegadytes Tremouilles & Bachmann, 1980

Miller, Kelly B., Michat, Mariano C. & Ferreira Jr, Nelson, 2024, Reclassification of Cybistrinae Sharp, 1880 in the Neotropical Region (Coleoptera, Adephaga, Dytiscidae), with description of new taxa, ZooKeys 1188, pp. 125-168 : 125

Paramegadytes Tremouilles & Bachmann, 1980 stat. nov.

Figs 26 , 27 , 56 , 63 , 70

Paramegadytes Trémouilles & Bachmann, 1980: 101.

Type species.

Dyticus glaucus Brullé, 1837: 46 by original designation.

Diagnosis.

Like Metaxydytes these species have both metatibial spurs apically simple, the medial margins of male abdominal sternite IX straight, and both males and females with two metatarsal claws, males with equal-length claws and females with the posterior claw reduced (Figs 26 , 27 ). Females also share the characteristic of the medial margins of the gonocoxosternite with a series of spinous setae (Fig. 63 ). The lateral pronotal margin has a diffuse, but distinctive lateral pale band. From Metaxydytes these specimens are larger with the metaventrite wings relatively broader (see above under Metaxydytes for details of diagnostic comparisons). Third instar larvae have (1) the median lobe of the frontoclypeus truncate apically with a tuft of setae (Fig. 70 ), (2) the median and lateral lobes of the frontoclypeus separated by a wide emargination (Fig. 70 ), and (3) the lateral lobes of the frontoclypeus bilobed (Fig. 70 ).

Phylogenetics.

This may be the sister genus to Metaxydytes (Figs 75 , 76 ; Miller et al. 2007) although here it is in an unresolved position relative to Nilssondytes , Metaxydytes and Megadytes + Cybister (Figs 75 , 76 ). See under Metaxydytes for further discussion.

Discussion.

There are currently two valid species in this genus, P. australis (Germain) and P. glaucus ( Brullé). Trémouilles and Bachmann (1980) characterized and differentiated them.

Figures

Figure 75. One of seven cladograms derived from parsimony analysis of 57 morphological characters from Cybistrinae and other Dytiscidae (len = 105, CI = 68, RI = 92) with characters mapped using ' fast' optimization in WinClada. Black hash marks indicate unambiguous changes, white hash marks indicate homoplasious changes or reversals. Numbers above hash marks are character numbers, those below hash marks are derived state numbers.

Figure 76. Consensus cladogram of seven equally parsimonious cladograms from parsimony analysis of 57 morphological characters from Cybistrinae and other Dytiscidae morphology.

Figures 15 - 29. Neotropical Cybistrinae species, metatarsal claws and tarsomere VI of males and females 15, 16 Cybister festae 17, 18 Cybister puncticollis 19, 20 Nilssondytes diversus 21, 22 Megadytes latus 23, 24 Megadytes parvus 25 species " IR 57 " (Ribera et al. 2008) 26, 27 Paramegadytes glaucus 28, 29 Metaxydytes fraternus. Scale bars: 1.0 mm.

Figures 51 - 57. Neotropical Cybistrinae species, male sternite IX, ventral aspect 51 Cybister festae 52 Cybister puncticollis 53 Nilssondytes diversus 54 Megadytes latus 55 Megadytes parvus 56 Paramegadytes glaucus 57 Metaxydytes fraternus. Scale bars: 1.0 mm.

Figures 62 - 66. Neotropical Cybistrinae species, female genitalia including left gonocoxosternite, ventral aspect 62 Metaxydytes fraternus 63 Paramegadytes glaucus 64 Bifurcitus lherminieri 65 Trifurcitus robustus 66 Cybister fimbriolatus. Scale bars: 1.0 mm.

Figures 67 - 71. Third instar larva, anterior clypeal margin 67 Bifurcitus magnus 68 Megadytes latus 69 Metaxydytes carcharias 70 Paramegadytes glaucus 71 Trifurcitus fallax.