Minyomerus imberbus [JF2015] Jansen & Franz 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 : 15-17

Taxon classification Animalia Coleoptera Curculionidae

Minyomerus imberbus [JF2015] Jansen & Franz sec. Jansen & Franz (2015) sp. n. Figs 5, 6

Diagnosis.

Minyomerus imberbus [JF2015] is best distinguished from other congenerics by a combination of characters, as follows. The interspersed setae on the body are minute and white. The anterior margin of the pronotum bears a reduced tuft of post-ocular vibrissae. The head is barely elevated between the eyes and head appears bare and smooth due to the small size of the setae. The spermatheca is distinct and has an elongate, cylindrical ramus, which is slightly thinner than corpus. Finally, the cornu is strongly recurved in the basal half, giving it a uniquely sinuate appearance.

Description - female.

Habitus. Length 3.69-5.82 mm, width 1.52-2.72 mm, length/width ratio 2.14-2.43, widest at anterior 1/4 of elytra. Integument dark reddish-brown to black. Scales slightly off-white to beige, semi-translucent or opaque. Setae minute, sub-recumbent, white.

Mandibles. Covered with whitish scales, with 2-3 longer setae.

Rostrum. Length 0.45-0.61 mm, anterior portion ca. 2.5 × broader than long, rostrum/pronotum length ratio 0.41-0.52, rostrum length/width ratio 1.21-1.24. Dorsal outline of rostrum square, anterior half of dorsal surface mesally concave, posterior half slightly convex. Rostrum in lateral view sub-rectangular; apical margin with 2 large vibrissae. Nasal plate defined by V-shaped, impressed lines, convex, integument covered with white scales. Margins of mandibular incision directed 20° outward dorsally in frontal view. Ventrolateral sulci strongly defined, beginning as a narrow sulcus posteriad of insertion point of mandibles, running parallel to scrobe, terminating in a ventral fovea. Ventrolateral margins slightly converging anteriorly.

Antennae. Dorsal margin of scrobe overhanging broadly (not forming a minute tooth). Funicle slightly longer than scape. Club similar in length to funicular antennomeres IV-VII, ca. 2.5 × as long as wide.

Head. Eyes separated in dorsal view by 4-5 × their anterior-posterior length, set off from anterior prothoracic margin by ca. 1/2 of their anterior-posterior length. Head between eyes slightly convex and rugoso-punctate.

Pronotum. Wider than long, length/width ratio 0.89-0.96, somewhat globular; median sulcus not apparent. Anterior margin arcuate, subtly incurved mesally, and somewhat produced dorsally; anterior constriction broad, posterior margin slightly arcuate. Pronotum in lateral view with minute setae inserted 2 × their length from anterior margin. Anterolateral margin with a reduced tuft of post-ocular vibrissae present, consisting of 3-5 setae, emerging near ventral 1/4 of eye; vibrissae achieving a maximum length sub-equal to anterior-posterior length of eye.

Scutellum. Usually exposed, lateral margins strongly incurved.

Pleurites. Metepisternum covered by elytron near posterior margin of metasternum.

Thoracic sterna. Mesocoxal cavities separated by distance 1/2 × width of mesocoxal cavity. Metasternum without apparent transverse sulcus; metacoxal cavities separated by 3 × their width.

Legs. Profemur/pronotum length ratio 0.78-1.05; 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 3/4 of distal surface and 1/6 length of femur. Protibia/profemur length ratio 0.86-0.93; protibia moderately stout; protibial apex with ventral setal comb situated on a slightly concave surface; mucro present as a minute, laterally projected tooth. Metatibial apex with almond shaped convex ity ringed by 12-14 short, spiniform setae.

Elytra. Length/width ratio 2.85-3.05; widest at anterior 1/4; anterior margins jointly ca. 2 × wider than posterior margin of pronotum; lateral margins slightly converging after anterior 1/4, more strongly rounded and converging in posterior 1/3. Elytra in lateral view nearly planar in region of disk, concave near anterior margin and posterior declivity; posterior declivity angled at 65-70° to main body axis. Punctures distinct, separated by 3-6 × their diameter; intervals weakly elevated.

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

Tergum. Pygidium (tergum VIII) sub-cylindrical.

Sternum VIII. Lamina sub-triangular; sclerotized region with pores throughout, more sclerotized medially.

Ovipositor. Coxites 1/2 as broad as long in dorsal view, porose throughout; styli glabrous.

Spermatheca. S-shaped; collum short, apically with a large, hood-shaped projection perpendicular to ramus, nearly equal in length and contiously aligned with curvature of bulb of ramus and ante-apically with a short, cylindrical projection, angled at ca. 45° to collum, nearly equal in length to collum and 1/3 length of ramus; collum short, obliquely rounded, sub-contiguous with, and angled at 90° to ramus; ramus elongate, cylindrical, slightly thinner than corpus; corpus not swollen, slightly thicker than ramus; cornu elongate, apically, gradually narrowed, strongly recurved and arched in basal 1/2, forming an inner angle of ca. 40°, with apical 1/2 perpendicular to collum and corpus, feebly sinuate.

Male.

Not available or known.

Comments.

Due to the limited number of specimens of this species, dissections of mouthparts could not be performed.

Etymology.

Named in reference to the relative lack of setae on the head; imberbus = beardless; Latin adjective ( Brown 1956).

Material examined.

Holotype - female "Pine Valley IBP, Valid. Site, Millard Co., Ut., 27 Jun. 73" (BYU). Paratype - "Pine Valley IBP, Valid. Site, Millard Co., Ut., 27 Jun. 73/ Host Artemisia spinescens [non-focal]" (BYU: 1 female).

Distribution.

This species is known from one locality in Millard County, Utah (Fig. 50).

Natural history.

Associated with budsage ( Artemisia spinescens D.C.Eaton [non-focal]; Asteraceae [non-focal]). It is unknown whether this species is parthenogenetic.