Peltariosilis gracilicornis, Biffi & Geiser, 2020

Biffi, Gabriel & Geiser, Michael, 2020, A revision of Peltariosilis Wittmer (Coleoptera: Cantharidae), a surprisingly diverse Amazonian radiation, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 60 (16), pp. 1-26 : 9-13

publication ID	https://doi.org/ 10.11606/1807-0205/2020.60.special-issue.16
publication LSID	lsid:zoobank.org:pub:3C128243-07E3-4435-A496-D8F50F68389E
persistent identifier	https://treatment.plazi.org/id/03CA7502-1633-3675-AC35-FC89DA7F3204
treatment provided by	Carolina
scientific name	Peltariosilis gracilicornis
status	sp. nov.

Treatment

Peltariosilis gracilicornis sp. nov.

( Figs. 6A View Figure 6 , 10G View Figure 10 , 12G View Figure 12 , 13D View Figure 13 , 14D, 16 View Figure 16 A-D)

Type series: HOLOTYPE ♂ ( INPA):“BRA, Amazonas, Novo / Aripuanã, lago Xadá / 05˚15′39″S 60˚42′32″W / iv.2005 // Em luz mista e BLB / F. Xavier, F.Godoi / & A. Lourido leg.” ( Fig. 6A View Figure 6 ).

Diagnosis: Antennae entirely testaceous yellow,slender, not swollen; pronotum and scutellum orange brown. Pronotum with low, small dorsal projections; laterobasal lobes slightly curved, directed dorsally and posteriorly, apex rounded, not slit. Scutellum lamellar, broad, with a wide forked projection; apices divergent, latero-anteriorly. Peltariosilis gracilicornis sp. nov. differs from all other species by the slender testaceous-yellow antennae,without tumescence, the shape of laterobasal bobes and dorsal projections of pronotum and, especially by unique shape of scutellar projection.

Description: Head black, except anterior margin of clypeus, orange brown; mandibles, labium, maxillae and palpi testaceous to light brown; antennae entirely testaceous yellow; pronotum and scutellum orange brown, slightly translucent; elytra dark brown, lighter at lateral margins and along suture; legs testaceous yellow to light orange brown slightly darker at apex of tibiae and tarsi; thorax and abdomen dark brown, except near the distal and lateral margins of abdominal ventrites.

Male: ( Fig. 6A View Figure 6 ): Antennae slender; antennomere I elongate, slightly wider apically, II short, cylindrical, III-XI cylindrical, not distinctly swollen. Pronotum ( Fig. 10G View Figure 10 ): anterior margin arched, continuous with frontolateral lobes; laterobasal lobes without lateral spines, forming a barely distinct angle or cusp; laterobasal lobe slightly curved, directed posteriorly and dorsally, apex rounded, not distinctly split; dorsal projections low, transverse, directed postero-dorsally, forming blunt lateral peaks barely reaching sides of pronotum. Scutellum ( Fig. 12G View Figure 12 ) lamellar, with a long forked projection anteriorly; scute- llar projection gradually narrowed at middle and widened toward the apex, forming a broad apical fork with divergent apices pointing latero-anteriorly. Elytra nearly parallel, apex rounded. Abdominal tergite VIII ( Fig. 13D View Figure 13 ) subquadrate, nearly as long as wide, lateral margins sinuous, wider medially; glandular pores not protruding; distal margin with a shallow rounded median notch. Ventrite VII ( Fig. 14D) wide, lateral margins parallel anteriorly and convergent posteriorly, apex rounded; internal margins slightly arched, divergent, halves broadly separated. Aedeagus ( Figs. 16 View Figure 16 A-D): ventral plaque of tegmen lateroventral, shorter than internal sac and ventral sclerites, flattened laterally, broad, lateral margins curved, apex rounded with an acute dorsal pointing tip; parameres fused at base and parallel apically, apex curved with small tip pointing dorsally; median lobe membranous, translucent; internal sac tubular, very elongate and broad, more sclerotised apically; one pair of paramedi- an dorsal sclerites straight and convergent at base, with divergent apices curved laterodorsally, apex acute; lateral sclerites indistinct, median dorsal sclerite elongated, narrowing apically, apex acute; ventral sclerites ventrally, partially flanking internal sac, very elongated, slen- der, slightly convergent apically, than apices divergent, acute, convergent, directed laterally.

Female: Unknown.

Etymology: The specific epithet gracilicornis is formed from the Latin words gracilis (slender) + cornis (“horn”, antenna), referring to the slender antennae.

Distribution: Brazil (Amazonas state) ( Fig. 18 View Figure 18 ).

Peltariosilis scutulata ( Wittmer, 1952) ( Figs. 6B View Figure 6 , 9 View Figure 9 A-D, 10H, 12H, 13E, 14E, 16E-H)

Silis (Peltariosilis) scutulata Wittmer, 1952: 203 , Delkeskamp 1977: 286.

Peltariosilis scutulata, Constantin 2010b: 16, 2017: 63 .

Type material examined: HOLOTYPE (“ Allotype ”) ♂ ( NHMB):“AmazonasMauans / Parko II 1941 // S./ scutulata / Wittm./ det. W.Wittmer // Allotypus // Naturhistorisches / Museum Basel / Coll. W. Wittmer // CANTHARIDAE / CANTH00018355 ” ( Figs. 9 View Figure 9 A-E) . PARATYPE ♂ ( NHMB): “ Amazonas / B. Constant / Parko.2.1941 // Paratypus // 3 // Naturhistorisches / Museum Basel / Coll. W. Wittmer // CANTHARIDAE / CANTH 00018445” ( Figs. 9 View Figure 9 F-J).

Other material examined: “ BRASIL. Roraima, Caracaraí / (Vila Caicubi,trilha Pupunha ) / 00˚59′27,1″S, 62˚05′55.8″W / 10.ix.2011 / Biffi,G.& Prado,L. R.col.// MZUSP 31233 View Materials ” (1 ♂, MZUSP 31233 View Materials ) ; “ BRASIL: Amazonas, Novo Airão, / Rod. AM 352 , Km-68, Igarapé / Mato Grosso, 17-31.VIII.2016, / 02˚48′58″S, 60˚55′18″W. / Malaise peq próximo igarapé / J.A. Rafael & F.F. Xavier leg.” (1 ♂, CEMT) ; “2395 // Est. Am 1. Km 104 / Mn. Am. Brasil / Em 5/68 / Col-Vários” (1 ♂, INPA) ; “ Tapuruquara / Rio Negro , AM / 26-27.XI.1962 / J. Bechyné

col. // Convênio / DZSP- Goeldi // MZUSP 31234 View Materials ” (1 ♂, MZUSP 31234 View Materials ) ; “ Rio Cauaburi / AM, Brasil / 9.XII.1962 / J. Bechyné col. // MZUSP 31235 View Materials ” (1 ♂, MZUSP 31235 View Materials ) .

Diagnosis: Antennae dark brown, except antennomeres I-II and X-XI,testaceous yellow to light orange brown;pronotum and scutellum orange brown; elytra dark brown, lighter at lateral margins and along suture.Antennomeres X-XI narrower than preceding ones. Pronotum with low, sharp dorsal projections; laterobasal lobes straight, di- rected dorsally and posteriorly, apex rounded, swollen. Scutellum with a long forked projection; apices parallel, pointing anteriorly. Peltariosilis scutulata is a member of a group of species with somewhat similar pronotum and scutellar projections. It differs from P. mitarakaemontis , P. brunneoapicalis sp. nov. and P. parviscutellaris sp. nov. by the robust apices of scutellar fork, from P.cleidecostae sp. nov. and P.brancuccii sp. nov. by the rounded apex of laterobasal lobes; from P.gracilicornis sp. nov. and P.flavicornis sp. nov. by the mostly dark brown antennae, and from P. orientalis sp. nov. by the width of dorsal projections of pronotum, reaching lateral margins.

Re-description: Head black, except anterior margin of clypeus, orange brown; mandibles, labium, maxillae and palpi testaceous to light brown; antennae mostly dark brown, except antennomeres I-II, ventral face of III, and X-XI testaceous yellow to light orange brown; pronotum and scutellum orange brown, slightly translucent; elytra dark brown, lighter at lateral margins and along suture; legs testaceous yellow to light orange brown slightly darker at apex of tibiae and tarsi; thorax and abdomen dark brown, except near the distal and lateral margins of abdominal ventrites.

Male: ( Fig. 6B View Figure 6 ): Antennae long; antennomere I elongate, slightly wider apically, II short, slightly wider apically, III-IX nearly cylindrical, narrower proximally, flat at ventral surface and globose at dorsal surface, IX-XI narrower, slender, filiform. Anterior margin of clypeus with a broad arcuate concave notch. Pronotum ( Fig. 10H View Figure 10 ): anterior margin broadly arched; frontolateral lobe narrow, projected laterally, sides behind frontolateral lobe slightly convergent; angles of laterobasal lobe rounded or barely obtuse; laterobasal lobe straight, directed posteriorly and dorsally, apex swollen, rounded, apparently split, forming juxtaposed dorsal and ventral flaps; apex of ventral flap with a short membranous projection; dorsal projections low, transverse, directed postero-dorsally, distal margin arcuate, forming an inner acute peak and lateral peaks barely reaching sides of pronotum. Scutellum ( Fig. 12H View Figure 12 ) with a long forked projection anteriorly; scutellar projection gradually narrowed, elongate and abruptly widened, forming apical fork with arched sides; apices of fork divergent, pointing latero-anteriorly. Elytra nearly parallel, apex rounded. Abdominal tergite VIII ( Fig. 13E View Figure 13 ) subquadrate, lateral margins broadly arched, wider medially,distal margin with a shallow median notch.Ventrite VII ( Fig. 14E) wide, lateral margins broadly arched, wider anteriorly, convergent posteriorly; posterior margins straight laterally, with a low rounded projection internally. Aedeagus ( Figs. 16 View Figure 16 E-H): ventral plaque of tegmen lateroventral, elongated, longer than internal sac and sclerites,flattened laterally, curved internally, narrow,wider at apex, apex broadly rounded with a dorsally curved acute tip; parameres fused at base and slightly divergent, regularly curved dorsally, apex narrowed or rounded with a small acute tip; median lobe membranous, translucent; internal sac elongated, narrow, straight, nearly as long as ventral, median and paramedian dorsal sclerites; one single median sclerite, elongated, narrow, apex acute; paramedian dorsal sclerites robust, strongly sclerotised, elongated, slightly curved dorsally and abruptly folded, with apex sharp, pointing dorsally; ventral sclerites slen- der, shorter than internal sac, apex acute, slightly divergent; lateral sclerites indistinct.

Distribution: Brazil (Roraima and Amazonas states) ( Fig. 18 View Figure 18 ).

Remarks: Type series of S. (P.) scutulata: Wittmer (1952) described only the male of Silis (Peltariosilis) scutulata from a type series composed of a holotype (from MNRJ) and an “ allotype ” (from Wittmer’s own collection, now housed at NHMB) from “ Brasilien, Manaus (Amazonas) 2.1941 leg. Parko”. Both specimens, located at NHMB, are males labelled as “ allotype ” and “ paratype ” – and not holotype. The “ allotype ” bears a locality label “Amazonas Mauans [lapsus for Manaus]” ( Fig. 9E View Figure 9 ), whereas the“ paratype ” bears a locality label “Amazonas, B. [Benjamin] Constant” ( Fig. 9J View Figure 9 ). The reason why the type specimens of S. scutulata are labelled as “ paratype ” and “ allotype ” is still unknown, but one of them actualy might comprise the holotype. The specimen labelled as “ allotype ” is here considered as the actual holotype of S. (P.) scutulata , given that that is the only specimen bearing a label with the type locality according to the original description. Fortunately, since the original description, this specimen had never been returned to the MNRJ, thus being saved from the fire that destroyed nearly the entire museum in September, 2018 ( Kury et al., 2018).

On the identity of P. scutulata: In the two most recent papers on the genus ( Constantin & Chaboo, 2016; Constantin, 2017), this species was reported to be widely distributed within the Amazonian forests, from French Guiana and Pará state ( Brazil) to Bolivia and Peru. With the limited amount of material available per locality, the diagnosis of the species was based only on external characters.

Now, our more extensive material and the examination of the male genitalia revealed clear differences between the populations in various parts of Amazonia, which lead us to the conclusion that P. scutulata sensu Constantin needs to be treated as a whole complex of species. What added to the confusion was the fact that Wittmer’s own type series already represents two different species, with the paratype from Benjamin Constant belonging to a different, undetermined species. The remaining specimens identified as P. scutulata by Wittmer himself turned out to belong to three additional species ( P. cleidecostae sp. nov., P. flavicornis sp. nov. and P. brancuccii sp. nov.). It appears that both Wittmer and Constantin interpreted the differences in pronotum structure, scutellar projection and antennal colouration as individual variability, but with our more extensive material some of these character turned out to be diagnostic for the different species.

With this in mind, we have to assume that the specimen illustrated by Constantin (2017) most likely doesn’t belong to P. scutulata either, but at the moment we are not sure which species to assign it to. In our restricted sense, P. scutulata is a species found only in parts of Amazonian Brazil, notably around Manaus.Some records from other areas mentioned by Constantin (2017) are still pending re-examination.