Araucariocladus amfractus, Nunes & Souto & Monteiro & Silveira, 2019

Nunes, V. C. S., Souto, P. M., Monteiro, R. F. & Silveira, L. F. L., 2019, A second species of Araucariocladus Silveira & Mermudes, with notes on the variation in antennomere numbers in this genus (Coleoptera: Lampyridae), Zootaxa 4571 (4), pp. 562-570 : 563-565

Araucariocladus amfractus sp. nov. Nunes, Souto & Silveira

( Figs. 1–5 , 7–16 )

Diagnosis. Colour pattern: overall dark-brown, but with a level of depigmented disc with paired round spots translucent on each side of the pronotum. Antenna with 17 or 18 antennomeres; pedicel three times shorter than antennomere III and slightly wider than long. Distance between antennal sockets as wide as 3/5 clypeal width. Labial palpomere III securiform, 1/3 longer than wide, sides divergent toward apex (in lateral view), ventral side longer than dorsal, apical margin longer than dorsal margin, shorter than ventral margin. Pronotum 1.5x wider than long, anterior margin somewhat sinuate, tapering anteriad, posterior margin almost straight.

Etymology. From latin adjective amfractus , which means sinuate. The name refers to the parameres, which are apically sinuate.

Type material. Holotype. BRAZIL: Minas Gerais, Itamonte, Parque Nacional do Itatiaia , 03/XII-05/I/2016, S 22° 21’ 34.1’’, W 44° 44’ 9.4’’, 2162m, male, Exp. PENSA RIO (MNRJ). Paratypes: BRAZIL: Rio de Janeiro, Itatiaia, Parque Nacional do Itatiaia , XII/2013, one male, R. Monteiro col. ( DZRJ 1795 ) ; idem, XII/2014, S 22° 25’ 01.0’’, W 44° 38’ 32.9’’, 1846m, one male, R. Monteiro col. ( DZRJ 1796 ) .

Males description. Coloration. Overall brown, with pronotum and elytra dark-brown ( Figs. 1–3 ). Pronotum sometimes (the two paratypes, not the holotype) with a paired of depigmented area (Supp. Mat.).

Morphology. Head ( Figs. 1–6 , 7–9 , 16 ). Head completely covered by pronotum ( Fig. 9 ). Antenna with 18 segments, but one paratype has 17 segments and the other is a teratological specimen, presenting an antenomere with double flagellum, and another apparently subdivided. Antennomeres subequal in length; pedicel slightly wider than long, 1/3 as long as antenommere III, III-X flabellate, flabellae of antennomeres III to subapical (XVI or XVII) increasing in length from III up to the antennomere X, then decreasing toward apex. ( Fig. 4–6 ). Eye as wide as 1/2 distance between eyes in frontal view ( Fig. 7 ). Distance between antennal sockets as wide as 3/5 clypeal width. Anterior margin of the clypeus with a slight depression and irregularly sclerotized ( Fig. 7 ). Maxillary palpomere IV> II> III> I. Labial palpomere III> II> I; III securiform, 1/3 longer than wide, sides divergent toward apex (in lateral view), ventral side longer than dorsal, apical margin longer than dorsal margin, shorter than ventral margin ( Figs 7, 8 , 16 ).

Thorax ( Figs. 3 , 8, 9 ). Pronotum 1.5x wider than long; anterior margin somewhat sinuate, with a shallow angle anteriad, with punctures small and shallow, posterior margin slightly sinuate, weakly projected medially ( Fig. 9 ). Hypomera 2x longer than wide ( Fig. 3 ). Mesoscutellum elongate and punctured, with a depression toward the posterior region, posterior margins rounded ( Fig. 9 ).

Abdomen ( Figs. 10–15 ). Pygidium with posterior margin slightly emarginate on median 1/2 ( Fig. 10 ) Pygidium 1/3 wider than long, lateral margins slightly rounded, posterior angle pronounced and acute, posterior margin rounded and slightly longer than posterior angles ( Fig. 10 ). Sternum VIII with posterior margin smoothly emarginate. Sternum IX oblong, lateral margins curved, posterior margin strongly acute ( Fig. 12 ). Aedeagus ( Figs. 13–15 ) with phallobase and basal 2/3 of parameres strongly sclerotized, phallus slightly less so, and apical 1/3 of paramere coriaceus. Paramere and phallus covered by campanuliform sensillae. Paramere with outer margin subparallel up to apical 1/5, then curved inwards, apical 1/3 narrowed toward apex and distinctly acute, subapically sinuate; phallus apically acute, dorsal plate with lateral margins slightly more sclerotized than central 1/2, apical 1/ 3 projected dorsally; ventral plate present in the middle of the phallus, weakly sclerotized, shaped like a isosceles triangle tapering apically; phallobase with posterior and right margins emarginate, emargination of the posterior margin shallow, with median suture conspicuous on the anterior region.

Females and immature stages unknown.

Distribution ( Fig. 18 ). All three individuals of Araucariocladus amfractus were caught at the Itatiaia National Park, in the upper montane forests of the Mantiqueira Mountain Range. One specimen was collected at 1846m and two at 2162m. At the latter site, the upper montane forest is intermingled with patches of Campos de Altitude, an open grassland formation.

Remarks. The new species Araucariocladus amfractus sp. nov. is structurally very similar to the type species, A. hiems . However, the two species can be readily distinguished by the following features: colour pattern entirely dark brown; body outline overall wider than in A. hiems , elytron almost 5x longer than wide (almost 6x in A. hiems ); labial palpomere III, 1/3 longer than wide, with sides divergent toward apex (in lateral view), ventral side longer than dorsal, apical margin longer than dorsal margin, shorter than ventral margin (sides sub-parallel, of equal length, palpomere 2x longer than wide in A. hiems ) ( Figs. 16, 17 ); pygidium with lateral margins rounded (straight in A. hiems ); and sternum VIII with posterior margin smoothly emarginate (strongly so in median 1/ 3 in A. hiems ).

All three specimens of the new species examined have an abdomen entirely covered by the elytra, which is in contrast to that observed in A. hiems , where at least the pygidium is exposed. It seems unlikely that such a difference would be the outcome of a fixation issue, as all Araucariocladus specimens have been so far fixed in the same medium (92% ethanol). Alternatively, this difference could be the outcome of between-species differences in the morphology of the internal organs.

Figures

FIGURE 18. Araucariocladus spp. has been collected at the Minas Gerais and Rio de Janeiro State, with A. amfractus sp. nov. endemic to the Itatiaia Massif (Mantiqueira Mountain Range) and A. hiems endemic to Serra do Mar massif (Serra dos Órgaos mountain range).

FIGURES 1–3. Araucariocladus amfractus sp. nov., male holotype, habitus dorsal. 1, dorsal; 2, lateral; 3, habitus ventral; Scale bar: 2.0 mm.

FIGURES 4–6. Araucariocladus spp., antenna. 4–5 A. amfractus sp. nov., 4, male holotype, 18 antennomeres; 5, male paratype, 17 antennomeres. 6, A. hiems, male, 17 antennomeres; Scale bar: 2.0 mm.

FIGURES 7–15. Araucariocladus amfractus sp. nov., 7–9, male holotype 7, male head, ventral; 8, male head, lateral; 9, pronotum, dorsal; 8–15, male paratype, terminalia: 10, sternum VIII and pygidium, ventral; 11, syntergite, dorsal; 12, sternum IX, dorsal; 13–15, aedeagus, 13, dorsal, 14, lateral, 15, ventral. Scale bar: 0.5 mm (7–9); 0.5 mm (10–15).

FIGURES 16–17. Araucariocladus spp., labial palp, dorsal view. 16, A. amfractus, male paratype. 17, A. hiems, male paratype. Scale bar: 0.125 mm.