Minyomerus cracens [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 : 49-51

Taxon classification Animalia Coleoptera Curculionidae

Minyomerus cracens [JF2015] Jansen & Franz sec. Jansen & Franz (2015) sp. n. Figs 27, 28

Diagnosis.

Minyomerus cracens [JF2015] is best differentiated from other congenerics by virtue of its elytra, which are each 4-5 × as long as broad in dorsal view. The elytral striae are strongly punctate. The elytra are constricted anteriorly, and narrower than the pronotum, widening thereafter near the humeri. This species also has a somewhat protuberant frons. The spermatheca of this species is unusually shaped, with the corpus somewhat bulbous, and the ramus either flattened somewhat or slightly elongate.

Description - female.

Habitus. Length 4.29-5.69 mm, width 1.57-1.97 mm, shape greatly elongate and cylindrical, length/width ratio 2.39-2.68, widest at anterior 1/5-1/4 of elytra. Integument dark brown to black. Scales with variously interspersed colors ranging from white to manila/tan to brown, in some specimens appearing semi-translucent (in others opaque) or with a pinkish opalescent sheen. Setae sub-recumbent.

Mandibles. Covered with white to opalescent scales, with 4 longer setae, dorsal pair arising from same fovea, and 1-2 shorter interspersed setae.

Maxillae. Cardo bifurcate at base with an inner angle of ca. 120°, inner (mesal) arm 2 × thicker and longer than outer arm, inner arm of bifurcation equal in length to apically outcurved arm, glabrous. Stipes sub-quadrate, 1.5 × longer than wide, roughly equal in length to inner arm of bifurcation of cardo. Galeo-lacinial complexsclerotized in apical 1/3, membranous and setose in posterior 2/3; dorsally with 8 apicomesal lacinial teeth; ventrally with 5 reduced lacinial teeth. Palpiger with a transverse row of setae near anterior 1/3; anterior 1/2 membranous, posterior 1/2 sclerotized, mesal and posterior margins emarginate.

Maxillary palps. Three-segmented; I with apical end facing mesally and forming a 45° 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 trapezoidal, convex laterally; apical margins feebly sinuate, angulate; lateral margins weakly incurved; posterior margin rounded. Labial palps 3-segmented, I with apexprojecting beyond margin of prementum, but not reaching apexof ligula; both with 1 apical seta; III slightly longer than II.

Rostrum. Length 0.46-0.73 mm, anterior portion 2-2.5 × broader than long, rostrum/pronotum length ratio 0.41-0.54, rostrum length/width ratio 0.91-1.19. Dorsal outline of rostrum sub-rectangular, anterior half of dorsal surface strongly impressed, posterior half deeply punctate. Rostrum in lateral view rectangular; anterior half of dorsolateral margins diverging somewhat; apical margin with 2 pairs of large vibrissae, each pair inserted just laterad of apexof each sinuation in a single fovea. Nasal plate well defined by V-shaped, impressed lines, slightly convex, integument partially covered with opalescent scales. Margins of mandibular incision directed 35° outward dorsally in frontal view. Ventrolateral sulci deeply and distinctly defined beginning as a notch dorsad of insertion point of mandibles, continuing parallel to scrobe, and terminating in a fovea ventrad of anterior margin of eye, interrupted and appearing as two sulci; sulci on either side of interruption offset from each other such that posterior portion begins ventrad of end of anterior portion. Dorsal surface of rostrum with short, linear, median fovea. Rostrum ventrally lacking foveae in line with insertion point of mandibles. Oral cavity with lateral margins broadly curved.

Antennae. Dorsal margin of scrobe overhangs slightly (broadly, not forming a sharp tooth) anterior to margin of eye by 1/4 of length of eye. Club similar in length to funicular antennomeres IV-VII, nearly 2.25 × as long as wide.

Head. Eyes separated in dorsal view by 4-5 × their anterior-posterior length, set off from anterior prothoracic margin by 1/3 of their anterior-posterior length. Head between eyes coarsely, deeply punctate and bulging.

Pronotum. Length/width ratio 0.98-1.06; widest between midpoint and anterior constriction. Anterior margin arcuate, lateral margins feebly curved and widening into a slight bulge just past midpoint of pronotum, posterior margin straight. Pronotum in lateral view with anterior sulcus continuing dorsally as a series of impressed punctures, anteriorly constricted region elevated and produced dorsally; with setae inserted 2 × their length from anterior margin. Anterolateral margin with a reduced tuft of 8-10 ocular vibrissae present, emerging below ventral margin of eye at a distance of 1/2 × dorsal-ventral length of eye, dorsal half of tuft with short setae, ventral half with setae 2-3 × longer, stopping just below ventral margin of scrobe; vibrissae achieving a maximum length nearly as long as 1/2-3/5 anterior-posterior length of eye.

Scutellum. Lateral margins slightly curved outward.

Pleurites. Metepisternum covered by elytron near posterior 1/5 of metasternum.

Thoracic sterna. Mesocoxal cavities separated by distance 1/4 × width of mesocoxal cavity. Metasternum with transverse sulcus apparent; metacoxal cavities widely separated by 3-4 × their width.

Legs. Hind tibiae with numerous longer setae. Profemur/pronotum length ratio 0.80-0.95; profemur with distal 1/5 produced ventrally as a short, semicircular projection covering tibial joint. Protibia/profemur length ratio 0.81-0.90; protibia relatively short and stout, in cross section sub-circular; protibial apexwith ventral setal comb set on curved surface; mucro present as a laterally projected tooth, longer than setal comb and 2 × width of stoutest setae. Protarsus with tarsomere I 1.5-2.0 × as long as II; II 2/3 × length of III, 2-3 × wider than long; II globular; I-III jointly similar in length to V. Metatibial apexwith oblique, almond shaped convex ity ringed by 10 short, widely separated, spiniform setae.

Elytra. Length/width ratio 1.74-3.54; widest at anterior 1/5-1/4; anterior 1/10 strongly constricted, narrower than posterior margin of pronotum, and more deeply punctured than remainder of elytra; anterior margins after constriction jointly 1.5-1.75 × wider than posterior margin of pronotum; lateral margins gently curving after anterior 1/4, more strongly rounded and converging in posterior 1/3. Posterior declivity very broadly and evenly arcuate dorsally, ventrally angled at 90° to main body axis. Elytral striae punctate; punctures clearly visible, separated by ca. 2 × their diameter; intervals slightly elevated; each interval medially with a row of sub-recumbent setae.

Abdominal sterna. Ventrite III elevated and set off from IV along lateral 1/4 of its length. Sternum VII mesally 1/2-3/5 × as long as wide, sub-trapezoidal; anterior margin weakly curved; posterior margin very broadly arcuate mesally.

Tergum. Pygidium (tergum VIII) sub-conical; posterior margin with many long, thin setae inserted along rim; medial 1/4 of anterior 1/2 of pygidium less sclerotized, sclerotized regions porose.

Sternum VIII. Lamina sub-quadrate; anterior edges each incurved forming a 90° angle with lateral margin; sclerotized region porose throughout, more sclerotized medially; posterior margin curved.

Ovipositor. Coxites slightly sclerotized anteriorly, strongly sclerotized in posterior 1/2, 2 × as long as broad; styli 1/2 × length of coxites, with 3-5 long setae near base.

Spermatheca. Comma-shaped; collum as long as corpus, swollen, equilateral; collum sub-contiguous with, and angled at 90° to ramus; ramus with apical edge straight, nearly equal in length to collum, posterior edge tapering off into cornu at a 45° angle, generally rounded in shape; corpus swollen, of equal thickness to collum, 2 × maximum width of cornu; cornu elongate, apically, gradually narrowed, strongly recurved in basal 1/5, nearly perpendicular to corpus along mesal 3/5, sinuate, and curved near apical 1/5 such that apexis parallel to collum and corpus.

Male.

Similar to female, except where noted. Length 3.86-4.18 mm, width 1.39-1.56 mm, length/width ratio 2.67-2.85. Rostrum length 0.56-0.62 mm, rostrum/pronotum length ratio 0.44-0.52, rostrum length/width ratio 1.28-1.30. Pronotum length /width ratio 1.04-1.11. Profemur/pronotum length ratio 0.76-0.80, protibia/profemur length ratio 0.76-0.83. Elytra length/width ratio 3.14-3.43.

Elytra. Generally shorter, but otherwise as female.

Abdomen. Sternum VII slightly more broadly arcuate posteriorly, 1/2-3/5 as long as wide. Pygidium (tergum VIII) with posterior margin with mesal 1/3 straight; posterior 1/3 punctate; anterior 2/3 rugose.

Aedeagus. Length/width ratio 4.24-4.70; lateral margins very slightly converging posteriorly, abruptly constricted and more strongly converging in region of ostium. In lateral view, width of pedon becoming gradually narrower posteriorly in anterior 3/4, ventral margins in posterior 1/4 becoming straight towards apex, then abruptly curving to meet dorsal margins at a sharp apical point; apexacutely angulate. Flagellum apically with a small, annuliform sclerite.

Etymology.

Named in reference to to the generally slender and elongate appearance of the elytra; cracens = slender or graceful; Latin invariable adjective ( Brown 1956).

Material examined.

Holotype - female "TEX. Gaines, Co. 5 mi. N, Seminole, 22 Aug-1970/ Collector: G.B. Marshall" (CWOB). Paratypes, same label information as female holotype (CWOB: 2 females); "TEX. Bailey Co., Muleshoe, 9-18-1970 night, G.B. Marshall/ Xanthocephalum sarothrae [non-focal]" (CWOB: 2 females); "TEX. Bailey Co., Muleshoe, 9-21-1970 night, G.B. Marshall/ Xanthocephalum sarothrae [non-focal]" (CWOB: 2 females); "TEX. Bailey Co., Muleshoe, 9-24-1970 night, G.B. Marshall/ Xanthocephalum sarothrae [non-focal]" (CWOB: 1 female); "N. Mex. 4 mi., E. Loco Hills, Otero Co., Oct. 4, 1970/ C.W. O’Brien, G. Richardson" (CWOB: 5 females); "N. Mex. Lea, Co. 19 mi. NE., Lovington, Oct. 4, 1970/ G. Richardson, C.W. O’Brien” (CWOB: 9 females); "N. Mex. Lea, Co. 1 mi. W, Lovington, Oct. 4, 1970/ C.W. O’Brien, G. Richardson" (CWOB: 1 female); "N. Mex. Jal, Lea Co., x-11-1970, L. & C.W. O’Brien / Xanthocephalum [non-focal]" (CWOB: 6 females); "Seagraves, TEX. Gaines, Co. x-10-1970, C.W. O’Brien / Xanthocephalum [non-focal]" (CWOB: 25 females) [10 females deposited at CMNC]; "TEX. Bailey Co., Muleshoe 9 30, -1970 night L. &, C.W. O’Brien / Xanthocephalum sarothrae [non-focal]" (CWOB: 21 females); "TEXAS: Pecos Co., Jct. FM 2023 & I-10, 30.86447°N, 102.58662°W, VIII-24-2007, E. G. Riley" (TAMU: 10 males, 13 females).

Distribution.

This species has been found in the desert and arid regions of eastern New Mexico and western Texas. It is likely that its range also includes western Oklahoma, based on similarity in habitat to the currently known distribution (Fig. 50).

Natural history.

Associated with broomweed ( Gutierrezia [non-focal] sp., including Gutierrezia sarothrae [Pursh] Britt. & Rusby [non-focal]; Asteraceae [non-focal]).