Miradessus Miller, Benetti & Michat, 2023

Miller, Kelly B., Benetti, Cesar J. & Michat, Mariano C., 2023, Miradessus gen. nov. from South America described for two species previously in Amarodytes Regimbart, 1900 and two new species (Arthropoda, Insecta, Coleoptera, Adephaga, Dytiscidae, Hydroporinae, Bidessini), ZooKeys 1176, pp. 13-28 : 13

Miradessus Miller, Benetti & Michat gen. nov.

Figs 1-8 , 9-17 , 18-29 , 30

Type species.

Amarodytes pulchellus Guignot, 1955 by current designation.

Diagnosis.

Miradessus belongs to the tribe Bidessini based on the presence of bisegmented lateral lobes (Figs 10 , 12 , 14 , 16 ) and a spermathecal spine (Fig. 17 ). Within Bidessini , the genus differs from most other genera in the following character combination: 1) occipital line absent (Figs 1-4 ), 2) basal pronotal striae present (Figs 1-4 ), 3) basal elytral stria absent (Figs 1-4 ), 4) sutural elytral stria absent (Figs 1-4 ), 5) transverse carina on elytral epipleuron at humeral angle absent, and 6) distinct marginal bead on anterior clypeal margin absent (Figs 1-4 ). Other genera share these features including Novadessus Miller, 2016, Bidessodes Régimbart, 1900, Neobidessodes Hendrich & Balke, 2009, the Amarodytes duponti group, and Amarodytes segrix Guignot, 1950. But Miradessus differs from all of these in the distinctive shape of the male genitalia (Figs 9-16 ). The male median lobe is very characteristically apically multilobed with a single, dorsal elongate and slender portion and a ventral section that is broad and bilobed (Figs 9 , 11 , 15 ) or flattened and elongate (Fig. 13 ). The lateral lobes are robust, and the bases are large and, in at least some species, covered with conspicuous tubercles (Figs 9 , 13 ). Members of the genus are also superficially quite distinctive from other Bidessini (see more below under Discussion).

Etymology.

This genus is named Miradessus from the Latin miror, meaning to admire, for the impressive color pattern of these beetles, and dessus, a common root for genera in the tribe Bidessini (gender masculine).

Discussion.

The species in this new genus are characterized by lateral lobes that are distinctly two-segmented like the majority of Bidessini taxa ( Biström 1988; Miller et al. 2006; Miller and Bergsten 2014; 2016; Miller 2016b;). Members of typical Amarodytes (including the type species, Amarodytes percosioides Régimbart, 1900) have single-segmented lateral lobes and belong within a clade sister to a clade characterized by two- or three-segmented lateral lobes (Benetti & Miller unpublished). Within the bisegmented lateral-lobe clade, these specimens do not fit well into any other genera (see Diagnosis above). They share some character combinations with Novadessus , Bidessodes , Neobidessodes , the Amarodytes duponti group, and Amarodytes segrix . In some ways they are most superficially similar to members of Bidessodes Régimbart, but specimens in that genus have series of very fine denticles along the posterior margins of the abdominal ventrites ( Miller 2017), which are lacking in Miradessus , and also have distinctly different male genitalia ( Miller 2017). Miradessus are similar to Neobidessodes , but that genus has simple male median lobes unlike the multilobed condition in Miradessus (Figs 9 , 11 , 13 , 15 ). Otherwise, they are not similar to other genera in the tribe and are unique because of the prominently apically multilobed male median lobe (Figs 9 , 11 , 13 , 15 ) which is not found in other genera of Bidessini .

Figures

Figure 30. Miradessus species, distributions.

Figures 1 - 8. Miradessus species 1 - 4 dorsal habitus 1 M. beni 2 M. plaumanni 3 M. pulchellus 4 M. rikae 5 - 8 prosternal process left surfaces of metaventrite metacoxa metatrochanter and metafemur 5 Miradessus beni 6 M. plaumanni 7 M. pulchellus 8 M. rikae. Scale bars: 1.0 mm (1 - 4); 0.5 mm (5 - 8).

Figures 9 - 17. Miradessus species 9, 10 M. beni, male aedeagus 9 median lobe and left lateral lobe, dorsal aspect 10 right lateral lobe, right lateral aspect 11, 12 M. plaumanni, male aedeagus 11 median lobe and lateral lobes, dorsal aspect 12 right lateral lobe, right lateral aspect 13, 14 M. pulchellus, male aedeagus 13 median lobe and left lateral lobe, dorsal aspect 14 right lateral lobe, right lateral aspect 15, 16 M. rikae, male aedeagus 15 median lobe and lateral lobes, dorsal aspect 16 median lobe and right lateral lobe, right lateral aspect 17 M. pulchellus, female genitalia, ventral aspect. Scale bar: 0.25 mm.

Figures 18 - 29. Miradessus species, primary type specimens and labels 18 - 20 M. beni, holotype specimen 18 dorsal habitus 19 ventral habitus 20 specimen labels 21 - 23 M. plaumanni, lectotype specimen 21 dorsal habitus 22 ventral habitus 23 specimen labels 24 - 26 M. pulchellus, holotype specimen 24 dorsal habitus 25 ventral habitus 26 specimen labels 27 - 29 M. rikae, holotype specimen 27 dorsal habitus 28 ventral habitus 29 specimen labels. 21 - 23 courtesy of M. Schwarz (OLML) 24 - 26 courtesy of M. A. Balke (ZSMG).