Cymatodera lucubrans Rifkind, 2020

Cymatodera lucubrans Rifkind , new species

zoobank.org/ urn:lsid:zoobank.org:act:

( Figs. 7 View Figs , 41, 42 View Figs )

Specimen Examined. Holotype male: Mexico, Michoacan, Laurales , Sept. 25, 1989, [collector label missing, but probably J. Beierl & E. Barchet, colls.] ( CNIN).

Description ( Holotype). Length: 14 mm. Color: Body reddish testaceous; head, mesoventrite, and abdominal ventrite 4 reddish brown; elytra stramineous/testaceous, with indistinct light brown transverse banding on anterior 1/2 and two angulate, narrow, transverse light brown fasciae on posterior 1/2 ( Fig. 7 View Figs ). Head: Surface rather densely, coarsely punctate and rugulose, clothed with fine, suberect and erect pale setae of various lengths; antenna elongate, slender; antennomeres 2–5 subconical, 6–10 subserrate; antennomere 2 about 1/3 the length of antennomere 3; antennomere 11 longer than antennomere 10, narrowed distally, apex subacute. Pronotum: Elongate, about 2× as long as wide; surface shining, finely, inconspicuously punctate, transversely rugulose, vestiture as on head. Elytra: Elongate (together almost 3× as long as broad), disc flattened above; sides subparallel, gradually, arcuately convergent from posterior 1/5 to dehiscent apices; surface shining, strial punctures coarse, deep, diminished in size and depth on posterior 1/5; vestiture moderately dense but inconspicuous, composed mostly of fine, suberect testaceous setae, intermixed with fewer longer, more robust suberect setae. Metaventrite: Broadly flattened at middle; surface densely spiculate, sparsely setose; carinae and tubercles absent. Abdomen: Integument shining, moderately densely but inconspicuously setose; ventrites 1–5 shallowly punctate and feebly roughened; ventrite 5 ( Fig. 41 View Figs ) broad, sides slightly oblique, posterior angles subacute, posterior margin very broadly, arcuately emarginate; ventrite 6 ( Fig. 41 View Figs ) trapezoidal, convergent posteriorly, sides subsinuate apically, angles produced, slightly upturned, their apices subacute; posterior margin with deep Vshaped emargination at middle; surface densely but shallowly rugulose, inconspicuously but quite densely clothed anteriorly with short, stiff, erect, testaceous setae; tergite 6 ( Fig. 42 View Figs ) oblong, feebly convergent posteriorly; underside biconcave; sides subsinuate posteriorly; posterolateral angles narrowly oblique (each giving rise to an elongate, setal dagger); posterior margin with a shallow, arcuate emargination on each side, and a deeper, broadly Ushaped inflection at middle. Aedeagus: Apex of phallus subsagittate.

Etymology. The specific name is derived from a Latin participle meaning “night worker”—a reference to the nocturnal habits of the genus to which this species belongs.

Distribution. Known from a single location in Michoacán, Mexico.

Diagnosis. The new species can be distinguished from congeners on the basis of a unique combination of color, elytral pattern, metaventral sculpturing, and the shape and sculpturing of the male pygidium. Its affinities doubtless lie with the two species described directly below, with which it shares remarkably similar facies. They can be distinguished by details of the ventral sculpturing and male pygidial shape: Among the three, only C. lucubrans combines a distinctly spiculate metaventral integument with a sixth abdominal tergite that is deeply emarginate at middle.

Discussion. Cymatodera lucubrans belongs to a group of central and southern Mexican species characterized by long, slender antennae that have antennomere 2 much shorter than antennomere 3, elongate body, testaceous elytra marked with dark, angular, transverse fasciae, and highly modified male pygidia that bear setal daggers on the sixth abdominal tergite. In collections, these species are often labelled as “ Cymatodera liturata Gorham ” or “ Cymatodera angulifera Gorham ,” but the latter are primarily Central American in distribution, entering Mexico only in the southernmost state of Chiapas. Furthermore, based on photographs of their holotypes, and examination of identified specimens, it is unlikely that there is even a particularly close affinity between them and the group to which C. lucubrans belongs. Within the C. lucubrans species group itself, determination of species discontinuities is challenging. The three species described in this paper share similar yet definably different male pygidia. Because they may be sympatric, I would normally be inclined to take a conservative approach by treating them as one species that happens to demonstrate an unusual plasticity (for Cymatodera ) of pygidial shape between populations. However, because each of these morphospecies combines a unique pygidial conformation with a different condition of metaventral sculpturing, I have chosen to describe them as separate species. It seems to me unlikely that members of a single species would demonstrate correlated variation of two characters (male pygidial shape and male metaventral sculpturing) that are both presumably implicated in mate recognition and reproductive isolation.