Minyomerus griseus [JF2015] (Sleeper, 1960) sec. Jansen & Franz (2015)

Jansen, M. Andrew & Franz, Nico M., 2015, Phylogenetic revision of Minyomerus Horn, 1876 sec. Jansen & Franz, 2015 (Coleoptera, Curculionidae) using taxonomic concept annotations and alignments, ZooKeys 528, pp. 1-133 : 76-83

Taxon classification Animalia Coleoptera Curculionidae

Minyomerus griseus [JF2015] (Sleeper, 1960) sec. Jansen & Franz (2015) comb. n. Figs 43, 44, 45

== AND = Piscatopus griseus Sleeper, 1960: 84 sec. Sleeper (1960)

Nomenclatural and taxonomic emendations.

Our phylogenetic analysis indicates that numerous significant characters are shared by all species herein assigned to Minyomerus [JF2015] and Piscatopus griseus sec. Sleeper (1960) which anchors the monotypic genus-level concept Piscatopus sec. Sleeper (1960) (see also O’Brien and Wibmer 1982; Anderson 2002). These include (Fig. 49): the widely separated and laterally positioned eyes, the ventrally directed scrobe (with overhanging dorsal margin), and the spiniform setae on the tarsi. The results of the analysis place Minyomerus griseus [JF2015] as sister to Minyomerus rutellirostris [JF2015], nested well within a clade of species of Minyomerus [JF2015] that also entails Minyomerus gravivultus [JF2015]. As such, we move to change Piscatopus sec. Sleeper (1960) to junior synonymy of Minyomerus [JF2015], and therefore also rename its sole member, Piscatopus griseus sec. Sleeper (1960), as Minyomerus griseus (Sleeper, 1960) [JF2015] in a new combination (see also Discussion).

Diagnosis.

Minyomerus griseus [JF2015] is readily distinguished from other congenerics by the separated procoxae and the size of the rostrum, which is narrower than the head. The eyes are relatively large, and the elytra are not noticeably punctate. The ramus of the spermatheca is cylindrical, somewhat bulbous, and basally constricted. The aedeagus is elongate, acutely angulate, and narrowing towards the apexmore strongly in the region of the ostium.

Redescription - female.

Habitus. Length 4.25-4.75 mm, width 1.77-2.03 mm, shape sub-cylindrical to ovate, length/width ratio 2.18-2.58, widest near anterior 1/2 of elytra. Integument dark reddish-brown to black. Scales with variously interspersed colors ranging from grey to white to yellow, in some specimens appearing semi-translucent (in others opaque) or with reddish or greenish opalescent reflections; scale color generally uniform throughout, sometimes with scales becoming lighter ventrally. Setae recumbent.

Mandibles. Covered with opalescent scales, with 6-7 longer setae.

Maxillae. Cardo as wide as palpomere III, bifurcate at base with an inner angle of ca. 100°, inner (mesal) arm 2 × longer than outer arm and of equal thickness, inner arm of bifurcation equal in length to apically outcurved arm. Stipes nearly square, equilateral, roughly equal in length to inner arm of bifurcation of cardo, glabrous. Galeo-lacinial complexmembranous and setose in posterior 2/3, sclerotized and somewhat emarginate anteriorly; dorsally with 8 apicomesal lacinial teeth; ventrally with 4 reduced lacinial teeth. Palpiger with a transverse row of setae; anterior 1/3 membranous, posteriorly sclerotized.

Maxillary palps. Palpomere I with apical end facing mesally and forming a 55° angle with base, I and II each with 2 apical setae; II with 1 mesoventral seta in addition to 2 apical setae.

Labium. Prementum roughly pentagonal, ventrally sub-planar throughout; apical margins sinuate, angulate, lateral margins broadly curved, posterior margin arcuate. Labial palps 3-segmented, I with apical 1/5 projecting beyond margin of prementum, but not reaching apexof ligula; III shorter than II.

Rostrum. Length 0.54-0.63 mm, anterior portion 2-2.5 × broader than long, narrower than head, rostrum/pronotum length ratio 0.51-0.53, rostrum length/width ratio 0.85-0.95. Dorsal outline of rostrum trapezoidal, posterior half of dorsal surface strongly rugose. Rostrum in lateral view nearly square; apical margin bisinuate, sinuations meeting to form a small median projection, and with 2 large vibrissae. Nasal plate very weakly defined by V-shaped, impressed lines, posteriorly planar, anteriorly concave, integument partially covered with opalescent scales. Margins of mandibular incision directed 25° outward dorsally in frontal view. Ventrolateral sulci weakly defined as a broad concavity dorsad of insertion point of mandibles (slightly notched in some specimens), running parallel to scrobe, becoming flatter posteriorly and disappearing ventrally. Dorsal surface of rostrum with median linear fovea at posterior end of rostrum equal in length to anterior-posterior length of eye. Rostrum ventrally with integument between 2 converging sulci (beginning at corners of oral cavity) slightly elevated. Oral cavity with lateral margins curved.

Antennae. Dorsal margin of scrobe overhanging slightly and forming a small tooth, anterior to margin of eye by 1/3 of length of eye. Terminal funicular segment lacking appressed scales, having instead a covering of apically-directed pubescence with interspersed sub-erect setae. Club nearly 3 × as long as wide.

Head. Anterodorsal margin of each eye slightly impressed, posterior margin strongly elevated from lateral surface of head; eyes separated in dorsal view by 4-5 × their anterior-posterior length, set off from anterior prothoracic margin by 1/4 of their anterior-posterior length. Head between eyes slightly bulging, appearing flat in some specimens. Head without any transverse post-ocular impression.

Pronotum. Length/width ratio 0.68-0.81, globular; surface finely punctate, though punctures somewhat obscured by scales; median sulcus absent. Anterior margin incurving mesally, posterior margin straight. Pronotum in lateral view with setae inserted 2 × their length from anterior margin. Anterolateral margin with a reduced tuft of 6-7 ocular vibrissae present, emerging near posterior 1/2 of eye, vibrissae longer ventrally, stopping near dorsal margin of scrobe, achieving a maximum length equal to 3/4 × anterior to posterior length of eye.

Scutellum. Margins straight. Pleurites. Metepisternum covered by elytron near posterior 1/4 of metasternu.

Thoracic sterna. Prosternal process complete or nearly so between coxae, coxae separated by distance equal to 1/6 × width of procoxal cavity. Mesocoxal cavities separated by distance 2/5 × width of mesocoxal cavity. Metasternum with transverse sulcus apparent; metacoxal cavities separated by 1.5-2 × their width.

Legs. Tibiae and trochanters of all legs with a single, hair-like, brown seta positioned on mesal surface, approximately 2 × length of adjacent setae. Profemur/pronotum length ratio 0.92-1.05; proximal 5/6 of profemur gradually widening, then abruptly constricted with distal 1/6 produced ventrally as a semicircular projection covering tibial joint; condyle of tibial articulation occupying 1/6 length of femur. Protibia/profemur length ratio 0.92-1.01; protibia moderately long and stout; protibial apexwith ventral setal comb recessed in a broadly concave groove; mucro present as a laterally projected tooth equal in length to nearby setae, triangular and equilateral. Protarsus with tarsomere I 1.5 × as long as II; II and III equilateral; I-II jointly similar in length to V. Metatibial apexwith almond shaped convex ity ringed by 10-11 short, spiniform setae.

Elytra. Length/width ratio 3.12-3.36; widest near anterior 1/2; anterior margins jointly 3/4-1 × width of posterior margin of pronotum; elytra slightly constricted near base, lateral margins gently and evenly curving thereafter, more strongly rounded and converging in posterior 1/4. Posterior declivity angled at nearly 70° to main body axis. Elytral striae finely punctate; punctures indistinct beneath appressed scales, separated by 4-6 × their diameter; intervals not elevated; scale color relatively uniform throughout; each interval medially with a row of recumbent setae.

Abdominal sterna. Ventrite III acutely anteromesally concave, posterior margin elevated and set off from IV along lateral 1/4s of its length. Sternum VII mesally 1/2-3/5 as long as wide; anterior margin straight.

Tergum. Pygidium (tergum VIII) sub-conical; porose on posterior 1/4; medial 1/3 of anterior 2/3 of pygidium less sclerotized.

Sternum VIII. Anterior 9/10 (spiculum ventrale) narrowly stylate; posterior 1/10 (lamina) sub-quadrate; anterior edges each incurved forming a 115° angle with lateral margin; less sclerotized medially; posterior margin medially incurved.

Ovipositor. Coxites 2/3 as broad as long in dorsal view; styli digitate, though not apically narrowed.

Spermatheca. Comma-shaped; collum highly reduced, apically with a small, hood-shaped projection nearly perpendicular to ramus, 3/5 × length of ramus and convex; ramus elongate, cylindrical, somewhat bulbous, with a basal constriction, 1.5 × thick ness of corpus; corpus slightly swollen; cornu elongate, apically, gradually narrowed, strongly recurved in basal 1/3, straight thereafter, extending nearly to extent of projection of collum, forming an inner angle of ca. 45° corpus.

Male.

Similar to female, except where noted. Length 4.17-4.37 mm, width 1.49-1.70 mm, length/width ratio 2.53-2.86. Rostrum length 0.55-0.62 mm, rostrum/pronotum length ratio 0.52-0.62, rostrum length/width ratio 0.90-0.98. Pronotum length/width ratio 0.76-0.82. Profemur/pronotum length ratio 0.94-1.16, protibia/profemur length ratio 0.92-1.00. Elytra length/width ratio 3.00-3.55.

Elytra. Elytral declivity more angulate, forming an 80° angle to main body axis, but otherwise as female.

Abdomen. Sternum VII similar to female. Tergum VII with posterior margin straight. Pygidium (tergum VIII) with posterior margin evenly arcuate; posterior 1/2 punctate; anterior 1/2 rugose.

Sternum VIII. Consisting of 2 sub-contiguous, sub-triangular sclerites; posterior margins widely angulate and with 6-8 setae. Spiculum gastrale 1/3 longer than pedon of aedeagus.

Aedeagus. Length/width ratio 3.96-4.40; lateral margins slightly converging posteriorly, more strongly converging in region of ostium. In lateral view, width of pedon nearly equal along anterior 3/4, ventral margins in posterior 1/4 becoming straight towards apex, meeting dorsal margins at a sharp apical point; apexacutely angulate. Flagellum with a large, narrowly elongate, tortuous, ampullate, apical sclerite, sclerite anteriorly gradually widened, constricted in anterior 1/4 and slightly widening anteriorly to form a small bulb, situated in anterior portion of flagellum.

Material examined.

Allotype - male "Presidio Tex, X-28-44, JH Russel/ On Larrea divericata [non-focal] foliage, 44-26373/ ALLOTYPE, Piscatopus griseus ♂, Sleeper [red]/ Piscatopus griseus Sleeper , Allotype, DET. SLEEPER [red]/ BLNO, 003007 [light blue]" (USNM). Paratype, same label information as male allotype (USNM: 1 male). Additional specimens examined: from same series as male allotype and paratype (USNM: 9 females, 8 males); "N. genus-N. sp., Atriplex canescens [non-focal], Presidio, T. 2376, Curculionidae , Det. L.L. Buchan." (NMSU: 1 female); "TX: Presidio Co., Presidio, on Atriplex canescens [non-focal]" (NMSU: 1 female, 4 males); "TEX. Presidio Co., Presidio, 8-27-1971 [some with VIII-27-1971], C.W. O’Brien / on Larrea tridentata [non-focal]" (CWOB: 8 females, 17 males; USNM: 1 female, 1 male); "Presidio Texas, 7-22-48 PresNo., 2376 JH Russel, Atriplex canescens [non-focal], 48-16744" (USNM: 18 females, 24 males); "Presidio, Tex, X-1-43, Presidio 1142/ on Atriplex canescens [non-focal]/ Lot. No. 43-11347" (USNM: 5 females, 4 males); "Presidio, Tex., IX-21-43, JH Russel/ on Atriplex canescens [non-focal] foliage" (USNM: 1 female); " Larrea divaricata [non-focal]/ nr. Presdio, Tex. 34522, X-28-54-11853" (USNM: 4 females, 5 males).

Distribution.

This species has been found in Presidio, Texas (USA); and likely is also present in Chihuahua (Mexico) (Fig. 52).

Natural history.

Associated with creosote bush ( Larrea tridentata [DC.] Coville [non-focal]; Zygophyllaceae [non-focal]) and four-wing saltbush ( Atriplex canescens [Pursh] Nuttall. [non-focal]; Asteraceae [non-focal]). Erroneously listed as associated with Larrea divaricata Cav. , which is not known to occur in this region.