Two new species of Passalus Fabricius (Coleoptera: Passalidae) from the western Brazilian Amazon with comments on the taxonomic limits of the subgenera Author Bevilaqua, Marcus Author Fonseca, Claudio Ruy Vasconcelos da text Papéis Avulsos de Zoologia 2020 Pap. Avulsos Zool., S. Paulo 2020-03-04 60 19 1 13 http://dx.doi.org/10.11606/1807-0205/2020.60.special-issue.19 journal article 10.11606/1807-0205/2020.60.special-issue.19 1807-0205 4985175 B723DFDD-1F03-4110-903A-A2B8A4CA7083 Passalus (Pertinax) deuterocerus sp. nov. ( Figs. 1 , 2 , 3A, B, C ) Type material: HOLOTYPE : ♂ ( INPA ). “ BRAZIL : Acre : Cruzeiro do Sul / BR 364 Sítio Rosalvo / 08°03′36.68″S , 72°23′18.48″W / 05-11.ix.2011 / Fernando Pinto, Gleic Sá col” . PARATYPES :“Cruzeiro do Sul / BR 364 Sítio Rosalvo / 08°03′36.68″S , 72°23′18.48″W / 05-11.ix.2011 / Fernando Pinto, Gleic Sá col. ( 1 ♂ , 4 ♀ , INPA ). Cruzeiro do Sul / BR 364 Sítio Rosalvo / 08°03′37.09″S , 72°23′18.29″W / 05-11.ix.2011 / Fernando Pinto, Gleic Sá col. ( 1 ♀ , INPA ). Cruzeiro do Sul / 05-15.iv.1981 / F.G. Mello col. ( 1 ♀ , INPA ). Feijó / [Ramal] Deusa – Interflúvio Envira/Purús / 08°30′20.98″S , 70°02′41.43″W / 05-11.ix.2011 / Fernando Pinto, Gleic Sá col. ( 1 ♂ , 1 ♀ , INPA ). Feijó / [Ramal] Deusa – Interflúvio Envira/Purús / 08°30′32.41″S , 70°02′47.77″W / 05-11.ix.2011 / Fernando Pinto, Gleic Sá col. ( 1 ♂ , 2 ♀ , INPA ).” Diagnosis: medium sized specimens ( 22-25 mm total length); body convex; anterior frontal edge straight or slightly convex coarsely punctated; posterior mediofrontal area with large and rounded cephalic nodule; latero + mediofrontal tubercles large and conspicuous, with acute apices attached to inner tubercles (which are larger and with rounded apices) by weak anterofrontal ridges; small secondary mediofrontal tubercles, small- er than the latero + mediofrontal tubercles, with acute apices, near to each other; secondary laterofrontal tubercles nearly inconspicuous with slightly obtuse apices; posterofrontal ridges strong, elevated and straight, attached to the central tubercle, which is small, flat, with only apex pronounced; lateroposterior tubercles conspicuous and transverse; mentum with a dilated mediobasal area and large, deep lateral scars; anterior angles of pronotum acute and protruded; mesosternal scars shallow, triangular-shaped, with opaque surface and presence of micro bristles; metasternal disc barely delimited, with group of punctures in posterior region; metasternal lateral grooves narrow and glabrous; aedeagus elongated and narrow, median lobe elongated, larger than basal piece and parameres together, containing two sclerotized plates (ventral view); parameres separated from basal piece by conspicuous suture (ventral view). Description Body ( Figs. 1-3 ): convex; size: medium ( 22-25 mm , total length). Head ( Figs. 1 A-C, 2A-B, 3A-B): Labrum: straight anterior border. Clypeus: hidden under frons, with anterior angles large, acute and positioned between latero + mediofrontal and secondary laterofrontal tubercles, visible in dorsal view; lateroclypeal pits deep. Anterior frontal edge: straight, sometimes slightly convex and narrow. Secondary mediofrontal tubercles: small, small- er than the latero + mediofrontal tubercles, with acute apices, near to each other. Latero + mediofrontal tubercles: large, conspicuous, with acute apices, projected forward. Secondary laterofrontal tubercles: small, almost inconspicuous, with obtuse apices. Mediofrontal area: caliciform 2.1× wider than long, shallow; with coarse punctures, scattered over anterior region, and an inconspicuous longitudinal groove between secondary mediofrontal tubercles. Cephalic nodule: large, wellmarked, rounded. Inner tubercles: large, conspicuous, with rounded apices, slightly larger than latero + mediofrontal tubercles, slightly near to each other than to the central tubercle. Anterofrontal ridges: straight, small, weak, sometimes inconspicuous. Posterofrontal ridges: elevated, strong, nearly straight, starting at apex of central tubercle. Central tubercle: conical, flat, with apex not free and dilated posteriorly. Lateroposterior tubercles: conspicuous, transverse, slightly distant from central tubercle, with evident apex. Laterofrontal areas: slightly deep and rough, surface with a few stretch marks. Lateropostfrontal areas: deep, with rough surface. Postfrontal area: shallow, smooth surface. Postfrontal groove: well-marked, lacking medial notch. Epicranial sutures: well-marked. Epicranial pits: deep. Anterior angles of head: well-developed, with acute apices, slightly smaller than latero + mediofrontal tubercles. Canthus ocular: apices almost straight, not reaching half of eye. Antennae: trilamellated, with small, robust lamellae, distal lamella wider than other two. Mouthparts ( Figs. 2B , 3B ): Ligula : tridentate, median tooth larger, narrower than lateral teeth. Hypostomal process: wide, glabrous, slightly close to mentum. Mentum: mediobasal area: dilated, smooth, glabrous, with slightly protruded anterior region lacking median notch; lateral lobes with apices externally rounded and slightly straight at the inner face; lateral scars large, deep, glabrous, unpunctate, rounded, sometimes slightly oval. Mandibles: incisor lobe with three well-formed apical teeth; suprainternal teeth robust; infrabasal pits inconspicuous. Maxillae: lacinia bidentate at apex. Prothorax: Pronotum ( Figs. 1A, C , 2A, C ): anterior edge slightly straight; anterior angles acute and protracted; marginal groove well-marked, deep, narrow, and punctate throughout, with apex dilated, reaching more than ⅓ of pronotal width; lateral fossae large, well-marked, deep and rounded, with group of coarse punctures. Prosternum ( Fig. 1B ): prepisternum with a few long, sparse setae on outer face; prepimerum with a few sparse bristled punctures; prosternelum rhomboidal, with acute base. Mesosternum ( Figs. 1B , 2D , 3B ): smooth, glabrous; mesosternal scars triangular-shaped, shallow, with opaque surface containing micro bristles, without punctures or pubescence. Metasternum ( Figs. 1B , 2E , 3B ): disc barely delimited, more dilated than lateral regions; punctation forming group of punctures on lateroposterior region; pubescence absent; lateral groove narrow, thinner than mesotibiae, deep, without punctures or bristles. Elytra ( Figs. 1A, C ): approximately 2.5× longer and 1.1× wider than pronotum; striae narrower than interstriae, marked by circular and inconspicuous punctures on dorsal striae, well-defined in lateral striae; epipleura and humeri glabrous. Legs ( Figs. 1 A-C, 2A, C, E): profemur with well-marked groove on anteroventral border not reaching apex; posteroventral border with a few setae near apex; protibiae not dilated; mesotibiae with one or two small spines on outer face; metatibiae with one small spine on outer face. Abdomen ( Fig. 1B ): sternite VII with incomplete and well-marked groove; sides rough. Aedeagus ( Fig. 2F ): Median lobe: narrower than parameres,almost as long as parameres and basal piece togeth- er; ventrally with two lateral sclerotized plates lacking at median region. Basal piece separated from parameres by distinct suture. Parameres ventrally, with median anterior region with central emargination; laterally, with rounded projections almost reaching half of median lobe length; dorsally, with unjoined projections. Basal piece ventrally, short, with convexity in posteromedian region; dorsally lateral projections separate. Etymology: The specific epithet derives from the union of two Greek words, “deúteros” (“secondary” or “double”) and “keros” (“horn” or “any hornlike projection”), in reference to the two secondary mediofrontal tubercles, the most remarkable feature of the species. Polymorphisms: The secondary mediofrontal tubercles may vary in size and distance from each other; the anterofrontal ridges may be almost absent in some specimens. Remarks: Due to the convex body, well-developed inner tubercles,barely delimited metasternal disc,and metasternal pubescence absent, Passalus deuterocerus sp. nov. is assigned to the subgenus Passalus (Pertinax) . It is very similar to P. latifrons Percheron, 1841 , P. morio Percheron, 1835 ,and especially to P.epiphanoides (Kuwert, 1891) .The differences between P.deuterocerus sp. nov. and P.latifrons are more pronounced because the new species has small- er size, two secondary mediofrontal tubercles, mesosternal scars, and absence of pubescence on posterior region of the pronotum ventrally,while P.latifrons is larger,has no secondary mediofrontal tubercles or mesosternal scars, and has pubescence on the posterior region of the pronotum ventrally ( Table 1 ). Passalus deuterocerus sp. nov. differs from P. morio by having acute latero + mediofrontal tubercles (obtuse in P. morio ), anterior frontal edge of the head thinner (which is thicker in P.morio ), presence of secondary mediofrontal tubercles (absent in P.morio ), and by the general shape of aedeagus ( Table 1 ). When comparing the new species with P.epiphanoides , the differences are more subtle and require attention. Reyes-Castillo (1973) redescribed P. epiphanoides adding some characters as interspecific variations, such as protruding edges of the median notch of the anterior frontal edge of the head forming two secondary mediofrontal tubercles and mesosternal scars, which may be presented as two triangular-shaped matte areas covered with submicroscopic spicules. However, a reexamination the specimens studied by Bevilaqua & Fonseca (2019) showed that these features are constant in series of specimens. A better analysis showed that these so-called polymorphic characters are diagnostic features that distinguish the two species.Thus, P.deuterocerus sp. nov. can be differentiated from P.epiphanoides by the narrower mediofrontal area ( Fig. 3A ); two secondary mediofrontal tubercles ( Fig. 3A ); mediobasal area of the mentum with rounded anterior region, without punctures or bristles ( Fig. 3B ); shallow mesosternal scars with slightly triangular shape with matte surface and presence of micro bristles ( Fig. 3C ); metasternal disc with a group of punctures on the lateroposterior region ( Fig. 3C ); narrower aedeagus, with median lobe with narrower sclerotized plates, parameres with median anterior emargination and basal piece with concavity at posterior edge. Passalus epiphanoides presents wider mediofrontal area ( Fig. 3D ), absence of secondary mediofrontal tubercles ( Fig. 3D ), mediobasal area of the mentum may have punctures or bristles and a notch in the anterior region ( Fig. 3E ), deep and oval or drop shape mesosternal scars with matt surface and presence of micro bristles ( Fig. 3F ), metasternal disc with a small group of punctures in the lateroposterior region ( Fig. 3F ), wider aedeagus, with median lobe with wider sclerotized plates, parameres with median convexity on the anterior edge and basal piece with convexity on the posterior edge. The main difference between P. deuterocerus sp. nov. and other species currently allocated in P.(Pertinax) is the presence of secondary mediofrontal tubercles, a characteristic that apparently belongs to the Rhodocanthopus group. However, other characters such as eyes reduction, presence of secondary inner tubercles and presence of large spines on the external face of the meso- and metatibia, besides the general shape of the aedeagus (Jiménez- Ferbans et al., 2016a), do not allow the new species to be allocate in this group. Furthermore, it seems to be more related to species belonging to P. (Pertinax) s. str. such as P. morio , P. latifrons , P. epiphanoides and P. convexus Dalman, 1817 . However, phylogenetic analysis that is in process may have clarified this issue further.