Protoconnus Franz, 1967

Jałoszyński, Paweł, 2018, Revision of the Neotropical genus Protoconnus Franz (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4392 (1), pp. 41-82 : 43-48

Protoconnus Franz

Protoconnus Franz, 1967: 716 . Type species: Protoconnus andicola Franz, 1967 (des. orig.).

Revised diagnosis. Body with distinct constrictions between head and pronotum and between pronotum and elytra; thick bristles present on head and prothorax; head short, subpentagonal, subhexagonal or round; in macrophthalmous species eyes are near middle, adjacent or nearly adjacent to antennal cavities and posteriorly often reaching or nearly reaching occipital constriction, in microphthalmous species eyes located anteriorly; occipital constriction slightly narrower than vertex; vertex not bulging posterodorsad; frontoclypeal groove absent; mandibles subtriangular, robust; submentum not delimited by lateral sutures; hypostomal ridges absent, but area laterad each maxilla is distinctly elevated and laterally delimited by groove; antennal insertions moderately broadly separated; antennae with variously distinctly delimited trimerous club; broadest site of pronotum in most species located behind middle, but in few at middle or even in front of middle; pronotum with variously distinct lateral edges (from strongly carinate and slightly raised to barely indicated or even absent) and five small antebasal pits connected by a narrow groove or impression (reduced in one species); basisternal part of prosternum vestigial, barely marked; prosternal process developed as a short, parallel-sided and weakly elevated carina, in intact beetles hidden between procoxae; notosternal sutures indiscernible, prosternum laterally completely fused with hypomera; inner (adcoxal) portion of each hypomeron not demarcated by hypomeral ridge but conspicuously elevated, its anterior and posterior portions developed as subtriangular projections, hypomeron typically with a median sinuate longitudinal groove beneath lateral pronotal carina (poorly marked in some species); mesoscutellum large and exposed in intact beetles; each elytron with two small but distinct asetose basal foveae, variously distinct humeral denticle and a longitudinal humeral carina or ridge that is indistinct in some species; mesoventral intercoxal process strongly carinate, keel-shaped, anteriorly fused with anterior ridge of mesoventrite, posteriorly with metaventrite; procoxal rests on mesoventrite large, subtrapezoidal and separated at middle, asetose and with diffuse margins; metanepisternum conspicuously broadened, shifted lateroventrad and exposed, separated from metaventrite by a narrow ridge, but anteriorly and posteriorly fused with metaventrite; metaventral intercoxal process short and subtriangular, with a distinct median notch, narrowly separating metacoxae; metendosternite with long and slender stem; aedeagus symmetrical or with slightly asymmetrical apical region, elongate, with poorly sclerotized and barely discernible endophallic structures and slender parameres bearing apical setae, bases of parameres forming subtriangular lobes directed toward base of median lobe.

Redescription. Body small, BL 0.52–1.45 mm, typically stout, rarely slender, with distinct constrictions between head and pronotum and between pronotum and elytra, moderately to strongly convex, light to dark brown.

Head ( Figs 1 , 5–6 , 14–15 ) divided into exposed anterior part and posterior 'neck' region ( Fig. 1 ; nr), the latter retracted into prothorax. Anterior part short, typically about as long as broad, flattened, subpentagonal, subhexagonal or round; eyes in most species large and occupying most of the lateral surface of head, adjacent or nearly adjacent to antennal cavities, coarsely faceted, bean-shaped and strongly transverse in relation to the long axis of the head, deeply emarginate or notched posteriorly (the emargination is shallow or absent in microphthalmous species and some females); tempora in species with very large eyes barely discernible or even absent, in species with smaller eyes tempora distinct; vertex ( Figs 1 , 14 ; vt) transverse, not bulging posterodorsad, in many specimens with diffuse posterior ridge demarcating it from transverse impression separating 'neck' region; occipital constriction ( Fig. 1 ; occ) only slightly narrower than vertex; frons ( Figs 1 , 14 ; fr) posteriorly confluent with vertex, subtrapezoidal, not demarcated from clypeus ( Fig. 1 ; cl) or delimited by a diffuse and broad impression. Gular plate ( Figs 5 , 15 ; gp) broad, gular sutures indiscernible or indistinct; posterior tentorial pits ( Figs 5–6 ; ptp) small, located in front of transverse impression demarcating the 'neck' region ventrally. Head with thick bristles distributed on posterior portion of vertex, tempora and genae.

Antennae shorter than body, slender, with variously distinct trimerous club.

Labrum ( Figs 1–3 ; lb) transverse with rounded ( Fig. 2 ) or broadly emarginate ( Fig. 3 ) anterior margin. Mandibles ( Figs 1–3 ; md) symmetrical, subtriangular and robust, in some species with small preapical mesal tooth ( Fig. 2 ; mt), more frequently lacking teeth ( Figs 3 , 14 ). Maxillae ( Fig. 4 ) generalized, as in all genera of Glandulariini ; maxillary palp with relatively elongate and small palpomere I ( Fig. 4 ; mxp1), long and broadened distad palpomere II ( Fig. 4 ; mxp2), enlarged palpomere III ( Fig. 4 ; mxp3) about 2.5–3 times as long as broad, broadest near middle or slightly distally to middle, and very slender, pointed palpomere IV ( Fig. 4 ; mxp4). Labium ( Figs 5–6 , 15 ) with transverse submentum ( Figs 5–6 , 15 ; smn) demarcated posteriorly from gular plate by shallow and diffuse impression, lacking lateral sutures, subtrapezoidal mentum ( Figs 5–6 , 15 ; mn); and short prementum bearing narrowly separated at bases labial palps with all palpomeres elongate ( Fig. 15 ; lp1–3) and a small, subrectangular ligula with a pair of bristles. Hypostomal ridges absent, but region posterolateral to each maxilla distinctly elevated and forming an elongate protuberance ( Fig. 6 ; arrow), which is laterally delimited by a longitudinal groove.

Pronotum ( Figs 7–8 , 14 ) in dorsal view semicircular or subtrapezoidal, broadest behind middle (in one species in front of middle), transverse to nearly as long as broad; anterior margin arcuate or straight, anterior corners weakly marked, strongly obtuse-angled and blunt, lateral margins rounded or at least partly nearly straight, posterior corners distinct, typically nearly right-angled and blunt, posterior margin arcuate, nearly straight or with two or three very shallow emarginations ( Fig. 7 ); pronotal base with five very small (often barely discernible) round and shallow antebasal pits ( Figs 7 , 14 ; abp) connected by distinct transverse antebasal groove ( Figs 7 , 14 ; abg), only in one species ( P. apaapa ) the groove and partly also the pits are reduced. Sides of pronotum with variously distinct lateral edges, typically visible in posterior half or third, carinate and slightly elevated ( Fig. 8 ; lc), in some species diffuse, indistinct or even absent; in most species there is a longitudinal and usually recurved hypomeral groove ( Fig. 6 ; hg) beneath the lateral carina. Sides of pronotum and hypomera (except for their inner, adcoxal portions) covered with thick bristles.

Prosternum ( Figs 5–6, 8 , 15 ) with its basisternal part ( Figs 5 , 15 ; bs) vestigial, so short that barely discernible; prosternal process ( Figs 5, 8 , 15 ; psp) developed as a short, parallel-sided carina, which is weakly elevated ( Fig. 8 ) and poorly visible between procoxae in intact specimens, area behind prosternal process deeply emarginated; notosternal sutures absent, prosternum completely fused with hypomera; hypomera ( Figs 5–6 , 15 ; hy) lacking hypomeral ridges, their adcoxal portions asetose and strongly elevated ( Fig. 6 ), their antero- and posteromesal portions developed as subtriangular projections ( Figs 6 , 16 , arrowheads).

Mesonotum ( Figs 9–11 ) small, subtriagular, with strongly transverse mesoscutum ( Fig. 10–11 ; sc2), distinct scutoscutellar suture ( Figs 10–11 ; sss), and subtriangular mesocutellum ( Figs 9–11 , 14 ; scl2), in intact specimens well visible between elytral bases.

Mesoventrite ( Figs 12–13 , 17 ) with narrow and indistinctly demarcated anterior ridge ( Figs 12 , 17 ; ar); mesoventral intercoxal process ( Figs 12 , 17 ; msvp) carinate, strongly elevated, keel-shaped (at least anteriorly), anteriorly connected with anterior ridge and posteriorly fused with metaventrite; mesoventral procoxal rests ( Figs 12 , 17 ; pcr) only slightly impressed, large, asetose, separated at middle and with diffuse margins; mesanepisterna and mesepimera forming together moderately large mesocoxal projections ( Fig. 12 ; msc) with mesocoxae inserted on their mesoventral portions.

Metaventrite ( Figs 12–13 , 17 ; v3) about as long as broad, with rounded sides; metanepisterna ( Figs 12–13 , 17 ; aest3) strongly modified, very broad and shifted ventrad, entirely exposed in ventral view in intact specimens, anteriorly and posteriorly fused with median region of ventrite ( Fig. 13 ), mesal margins of anepisterna well-marked by an arcuate ridge often accompanied by a shallow impression; metaventral intercoxal process ( Figs 12 , 17 ; mtvp) short and narrow, subtriangular with posteromedian notch, narrowly separating metacoxae.

Metendosternite ( Fig. 13 ) with elongate and slender stalk ( Fig. 13 ; mfst) and divergent lateral furcal arms ( Fig. 13 ; lmfa).

Elytra ( Figs 9 , 14 ) oval, each with two small but usually distinct asetose basal foveae ( Figs 9 , 14 ; bef), located in a shallow basal impression; humeral calli distinct and developed as longitudinal protuberances, with humeral denticles ( Figs 9 , 14 ; hd) and usually with an elongate humeral carina ( Fig. 9 ; hc), which can be diffused and indistinct in some species.

Hind wings in most species absent.

Legs moderately long and slender; procoxae and mesocoxae oval, metacoxae strongly transverse; all trochanters short; all femora weakly clavate; tibiae long and straight; tarsi short and robust.

Abdomen short, usually shorter than metaventrite, sternites unmodified, suture between VII and VIII indistinct.

Aedeagus ( Figs 24–33 , 40–47 , 54–61 , 68––83 , 86–89 ) symmetrical or with slightly asymmetrical apical region, elongate, often slender, in most species with large basal capsule and distal region strongly narrowing distad, only in two species ( Figs 86–89 ) the distal region is about as broad or even broader than basal capsule; endophallic structures weakly sclerotized and barely discernible; dorsal foramen distant from base of median lobe; parameres present, slender, in some species modified (with their apices bent or broadened), apical setae present, bases of parameres developed as subtriangular lobes directed toward base of median lobe.

Spermatheca sclerotized and globular.

Sexual dimorphism usually distinct; males of most species have very large eyes occupying nearly entire length of head between antennae and occipital constriction, whereas in females the eyes are slightly to much smaller, and consequently tempora are longer.

Distribution and composition. Protoconnus comprises 25 species (11 described previously, including 10 originally placed in Protoconnus and one transferred from Euconnus , and 14 described as new) distributed in Central and South America ( Fig. 101 ); most species inhabit the eastern slopes of the Andes.

Figures

FIGURE 101. Distribution of nominal Protoconnus species.

FIGURES 1–4. Morphological structures of Protoconnus spp. (undetermined sp. 1 (1–2, 4) and sp. 2 (3), both from Ecuador). Head in dorsal view (1), mandibles, clypeus and labrum in dorsal view (2–3); maxilla in dorsal view (4). Abbreviations: cl, clypeus; fr, frons; gal, galea; lac, lacinia; lb, labrum; md, mandible; mt, mesal tooth; mxp1–4, maxillary palpomere I–IV; nr, 'neck' region; occ, occiput; pt, prostheca; vt, vertex.

FIGURES 5–8. Morphological structures of Protoconnus sp. (undetermined sp. 1, Ecuador). Head and prothorax in ventral (5) and lateroventral (6) view; prothorax in dorsal (7) and anterior (8) views. Abbreviations: abp, antebasal pit; abg, antebasal groove; bs, basisternal part of prosternum; bst, basistipes; cd, cardo; gp, gular plate; hg, hypomeral groove; hy, hypomeron; lc, lateral carina; mn, mentum; mst, mediostipes; pcx, procoxa; pf, profurca; prn, pronotum; psp, prosternal process; ptp, posterior tentorial pit; smn, submentum. Arrow shows expanded admaxillar region; arrowheads show anterior and posterior projections of adcoxal portions of hypomera.

FIGURES 14–17. Morphological structures of Protoconnus volcanbaru sp. n. Head, prothorax and elytral base in dorsal view (14); head, prothorax and anterior portion of mesoventrite in ventral view (15); adcoxal region of hypomeron in ventral view (16); pterothorax in ventral view (17). Abbreviations: abg, antebasal groove; abp, antebasal pit; aest3, metanepisternum; ar, anterior ridge; bef, basal elytral fovea; bs, basisternal part of prosternum; fr, frons; gp, gular plate; hd, humeral denticle; hy, hypomeron; lc, lateral carina; lp1–3, labial palpomere I–III; mn, mentum; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; pcr, procoxal rest; pre, prepectus; psp, prosternal process; scl2, mesoscutellum; smn, submentum; v3, metaventrite; vt, vertex. Arrowhead shows anterior projection of adcoxal portion of hypomeron.

FIGURES 9–13. Morphological structures of Protoconnus spp. (undetermined sp. 1 (9–10, 12) add sp. 2 (11, 13), both from Ecuador). Elytral bases and mesoscutellum in dorsal view (9); mesoscutellum in dorsal view (10–11); pterothorax in ventral view (12–13). Abbreviations: aest3, metanepisternum; ar, anterior ridge; bef, basal elytral fovea; hc, humeral carina; hd, humeral denticle; lmfa, lateral metafurcal arm; mfst, metafurcal stem; msc; mesocoxal projection; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; pcr, procoxal rest; pre, prepectus; sc2, mesoscutum; scl2, mesoscutellum; sss, scutoscutellar suture; v3, metaventrite.

FIGURES 24–33. Aedeagi of Protoconnus species. Protoconnus andicola Franz (24–25); P. venezolanus Franz (26–27); P. bolivianus Franz (28–29); P. comarapae Franz (30–31); P. princeps (Franz) (32–33).

FIGURES 40–47. Aedeagi of Protoconnus species. Protoconnus araguanus Franz (40–41); P. paraguayanus Franz (42–43); P. peruensis Franz (44–45); P. robustus Franz (46–47).

FIGURES 54–61. Aedeagi of Protoconnus species. Protoconnus quillabambanus sp. n. (54–55); P. ecuadoranus sp. n. (56– 57); P. napoanus sp. n. (58–59); P. impressifrons sp. n. (60–61).

FIGURES 68–75. Aedeagi of Protoconnus species. Protoconnus angustus sp. n. (68–69); P. maximus sp. n. (70–71); P. acutus sp. n. (72–73); P. minusculus sp. n. (74–75).

FIGURES 76–83. Aedeagi of Protoconnus species. Protoconnus costaricanus sp. n. (76–77); P. tunarianus sp. n. (78–79); P. magnus sp. n. (80–81); P. apaapa sp. n. (82–83).

FIGURES 86–89. Aedeagi of Protoconnus species. Protoconnus volcanbaru sp. n. (86–87); P. inexpectatus sp. n. (88–89).