Beardius longissimus (Mendes & Andersen, 2009) Pinho & Andersen, 2021

Pinho, Luiz Carlos & Andersen, Trond, 2021, Neotropical Nilothauma Kieffer, 1921 (Diptera, Chironomidae): Key, eleven new species, re-descriptions, new combination and new records, ZooKeys 1033, pp. 81-125 : 81

Beardius longissimus (Mendes & Andersen, 2009) comb. nov.

Nilothauma longissimum Mendes & Andersen, 2009: 26

Material examined.

Type material, as in Mendes and Andersen (2009).

Additional material.

8 males, slide-mounted: Brazil, Bahia, Camacan, RPPN Serra Bonita, Trilha Bapeba , 15°20'35"S, 39°33'34"W, 4.xi.2009, light trap, A.R. Calor et al. leg . 3 males, slide-mounted, as previous, except: 15°23'32"S, 39°33'53"W, 2.xi.2009. 1 male, slide-mounted, as previous, except: 03.ii.2009. 1 male, slide-mounted, as previous, except: córrego 2, 15°23'10"S, 39°34'03"W, 819 m a.s.l., 01.viii.2008, light trap, A.R. Calor, L.S. Lecci, L.C. Pinho & R.A. Moretto leg. 1 male, slide-mounted: Brazil, São Paulo, PE Serra do Mar, Ubatuba, Picinguaba , Camburi stream, 09.ix.2006, light trap, M.R. Spies & A.E. Siegloch leg.

Remarks.

Pinho et al. (2013) found that the "presence of apical thin setae on inferior volsella" (character 74, state 1), i.e. a group of two, rarely three, slender simple setae at the very tip of the inferior volsella, in addition to subapical, stouter setae, is the only synapomorphy of Beardius Reiss & Sublette, 1985 in the adult stage. In fact, the character is shared by all species of Beardius and is not found elsewhere, except in Nilothauma longissimum Mendes & Andersen, 2009, a species that was considered to be sister to all remaining Nilothauma by Mendes and Andersen (2009) in a phylogenetic analysis with Paratendipes Kieffer and Pseudochironomus Malloch as outgroups. The comparatively-high antennal ratio in N. longissimum (AR> 1.00) is the only exception in Nilothauma , which generally have very low antennal ratios (AR <0.40). Further, the venarum ratio (VR) seems to be low in N. longissimum compared to other Nilothauma species; other characters in N. longissimum are consistent with the current diagnosis of Beardius . We therefore propose the new combination and emend the diagnosis of Nilothauma accordingly.

Distribution.

The species was originally described from São Paulo State, south-eastern Brazil by Mendes and Andersen (2009); the range is now extended to Bahia State in north-eastern Brazil.