Minyomerus constrictus [JF2015] (Casey, 1888) 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 : 17-23

Taxon classification Animalia Coleoptera Curculionidae

Minyomerus constrictus [JF2015] (Casey, 1888) sec. Jansen & Franz (2015) Figs 7, 8

== AND = Elissa constricta Casey, 1888: 272 sec Casey (1888) (synonymized by Kissinger 1964: 30)

Diagnosis.

Minyomerus constrictus [JF2015] is most readily distinguished from other congenerics by the strong anterior “constriction” of the pronotum. The elytral setae are also very thin and setiform, especially on the disk, with setae apically tapering to a fine point, rather than being broadly rounded. The ocular vibrissae are well-developed in this species, and the eye is relatively large compared to other species. The spermatheca has the ramus bulbous, but tapered basally. The aedeagus is abruptly constricted apically.

Redescription - female.

Habitus. Length 3.33-4.17 mm, width 1.44-1.74 mm, length/width ratio 2.31-2.47, widest at anterior 1/3 of elytra. Integument black on tagmata and elytra, light to dark orange-brown on other appendages. Scales with variously interspersed colors ranging from white to manila/beige to coffee brown, in some specimens appearing semi-translucent (in others opaque) or with an opalescent sheen; scales on most specimens becoming lighter ventrally, but some specimens with venter of same coloration as dorsum. Setae very short, fine, white or translucent, becoming longer, thicker, and more erect on lateral margins of head and prothorax, humeri, and venter.

Mandibles. Covered with white scales, with 2 long setae dorsally, 2 long setae vetrolaterally, and 1 shorter seta between these.

Maxillae. Cardo bifurcate at base with an inner angle of ca. 125°, inner (mesal) arm 2 × longer than outer arm, inner arm 2 × width of outer arm, inner arm of bifurcation equal in length to apically outcurved arm. Stipes sub-quadrate, 1.25-1.5 × wider than long, roughly equal in length to inner arm of bifurcation of cardo, glabrous. Galeo-lacinial complex apically incurved (mesally); setose in basal 2/3; dorsally with 9 apicomesal lacinial teeth (1 of which is dorsad of mesal margin; ventrally with 5 reduced lacinial teeth. Palpiger with a transverse row of 2 setae, sclerotized on basal 2/3.

Maxillary palps. I and II both apically oblique, apical ends facing mesally and forming a 45° angle with base, I and II each with 2 apical setae.

Labium. Roughly trapezoidal; apical margins sinuate, weakly angulate; lateral margins straight; basal margin arcuate. Labial palps 3-segmented, I with apical 1/2 projecting beyond margin of prementum, reaching beyond apex of ligula; I and II both with 1 apical seta; III slightly longer than II.

Rostrum. Length 0.49-0.63 mm, anterior portion 2-3 × broader than long, rostrum/pronotum length ratio 0.59-0.64, rostrum length/width ratio 1.15-1.37. Dorsal outline of rostrum sub-rectangular, anterior half of dorsal surface impressed. Rostrum in lateral view sub-rectangular; basal half of dorsolateral margins strongly converging anteriorly, anterior half slightly divergent; apical margin with sinuations meeting mesally to form a small point, with 2 large vibrissae. Nasal plate defined by Y-shaped lines, concave mesally, covered white scales and with interspersed, erect, laterally directed setae. Margins of mandibular incision curved, directed 10-15° outward dorsally in frontal view. Ventrolateral sulci weakly defined as a broad concavity dorsad of insertion point of mandibles, running parallel to scrobe, becoming flatter posteriorly and disappearing ventrally. Dorsal surface of rostrum with median sulcus running from fovea at posterior end of anterior half rostrum to midpoint of posterior half of rostrum. Rostrum ventrally without median fovea. Oral cavity with lateral margins straight, diverging.

Antennae. Small tooth formed by overhanging dorsal margin of scrobe anterior to margin of eye by 1/2 of length of eye. Club nearly 3 × as long as wide.

Head. Eyes strongly impressed, posterior margin level with lateral surface of head; eyes separated in dorsal view by 3-4 × their anterior-posterior length, set off from anterior prothoracic margin by 1/4 of their anterior-posterior length.

Pronotum. Length/width ratio 0.80-0.93, globular; surface finely punctate; median sulcus absent. Anterior margin straight, lateral margins curved and widening into a bulge near anterior 2/5 of pronotum, thence curved towards posterior margin, posterior margin incurved. Pronotum in lateral view sub-cylindrical to slightly globular, with setae that just reach beyond anterior margin. Anterolateral margin with a tuft of post-ocular vibrissae present, emerging near dorsal 1/4 of eye, becoming gradually, evenly longer ventrally, stopping just above ventral 1/4 of eye; vibrissae achieving a maximum length 2/3 × anterior-posterior length of eye.

Scutellum. Equilateral to slightly longer than wide.

Pleurites. Metepisternum covered by elytron near anterior 1/5 of metasternum; a deep fovea present just basad of triangular projection of metepisternum.

Thoracic sterna. Mesocoxal cavities separated by distance1/3 × width of mesocoxal cavity. Metasternum with a transverse sulcus just posteriad of anterior margin, can be hidden by scales in some specimens; posteriorly a large median fovea between ventrite III and metasternum, antero-mesally planar, turned inward 25° and planar in posterior 1/2; metacoxal cavities widely separated by 3-4 × their width.

Legs. Profemur/pronotum length ratio 1.04-1.15. Protibia/profemur length ratio 0.87-0.94; protibia with ventral setal comb situated on a mesally incurved edge; mucro reduced to a very small apically projected tooth. Protarsus with tarsomere III equilateral; II broadly conical, III bifid; I and III jointly similar in length to V. Metatibial apex with almond shaped convex ity with a row of 5 short, widely separated, spiniform setae.

Elytra. Length/width ratio 2.90-3.20; widest at anterior 1/3; anterior margins jointly 1.5-2 × wider than posterior margin of pronotum; lateral margins sub-parallel after anterior 1/6, more strongly rounded and converging in posterior 1/4. Elytra in lateral view convex, mesally somewhat planar on dorsum; posterior declivity angled at nearly 80° to main body axis. Elytra very finely punctate, punctures not visible in some specimens, separated by 8 × their diameter; intervals not elevated.

Abdominal sterna. Scales similar to elytra, in some specimens of a lighter color; III with midregion planar posteriorly, anteriorly incurved to a mesal fovea on anterior margin, elevated and set off from IV along lateral 1/3 of its length. Sternum VII mesally 2/5 × as long as wide; setae darkening, lengthening, and becoming more erect in mesal 1/3; anterior margin weakly curved.

Tergum. Pygidium (tergum VIII) sub-cylindrical, medially with a patch of very short, fine setae.

Sternum VIII. Posterior 1/8 (lamina) square; anterior edges each incurved forming a 90° angle with lateral margin.

Ovipositor. Coxites in dorsal view nearly as long as broad; styli as long as coxites, glabrous.

Spermatheca. Comma-shaped; collum extremely short, apically with hood-shaped projection at 45° to central axis of ramus, 3/4 × length of ramus and contiously aligned with curvature of bulb of ramus; collum sub-contiguous with, and angled at 45° to ramus; ramus spherical, equal in length to width of corpus; corpus swollen, 1.5 × width of cornu; cornu elongate, apically, gradually narrowed, basal 3/4 angled at nearly 90° to corpus, gently curved along mesal 1/2, and recurved near apical 1/4 such that apex is sub-parallel to corpus.

Male.

Similar to female, except where noted. Length 2.78-3.52 mm, width 1.12-1.38 mm, length/width ratio 2.49-2.63. Rostrum length 0.39-0.60, rostrum/pronotum length ratio 0.47-0.67, rostrum length/width ratio 1.15-1.55. Pronotum length/width ratio 0.82-0.91. Profemur/pronotum length ratio 0.83-1.16, protibia/profemur length ratio 0.92-0.97. Elytra length/width ratio 2.97-3.34.

Elytra. Generally narrower relative to pronotum, but otherwise as female.

Abdomen. Sternum VII slightly more broadly arcuate posteriorly, 3/5 as long as wide. 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; without median, sub-trapezoidal projection.

Aedeagus. Length/width ratio 3.54-3.76; 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; apex acutely angulate. Flagellum apically with a large, narrowly elongate, tortuous, ampullate sclerite, sclerite anteriorly gradually widened, constricted in anterior 1/4 and slightly widening anteriorly to form a small bulb.

Material examined.

Holotype - female "●Ari [Casey locality code: Yuma Gila Valley, December 1886]/ Casey bequest 1925/ Type USNM 35006/ Elissa constricta Cas. " (USNM). Additional specimens examined: "Cal. Kelso Sand Dunes, S. Berdo. Co. IV-7-1966, L & C.W. O’Brien” (CWOB: 2 females, 2 males); "CAL. S. Berdo. Co. 3 mi. NW. Vidal W. Gagne, III-17-1967" (CWOB: 3 females, 1 male); "Ariz. 13 mi. S. Ajo, Pima Co., IV-2-1966, L & C.W. O’Brien / Larrea tridentata [non-focal]" (CWOB: 8 females, 4 males) [4 females, 2 males deposited at CMNC]; "Boulder Dam, Ariz/ Collection of Vasco M. Tanner" (CAS: 1 female, 2 males; BYU: 3 females, 1 male); "CALIF: Inyo Co., Eureka Valley, January 1978, Giuliani, Hardy, and Andrews/ Eureka Valley, transect anti-freeze pit trap, no. 8" (CSCA: 1 female, 2 males); "CALIF: Inyo Co., Eureka Valley, January 1978, Giuliani, Hardy, and Andrews/ Eureka Valley, transect anti-freeze pit trap, no. 8" (CSCA: 1 female, 2 males); "CALIF: Inyo Co., Eureka Valley, February 1978, Giuliani, Hardy, and Andrews/ Eureka Val ley, transect anti-freeze pit trap, no. 7 [part of series, includes 7 & 8]" (CSCA: 1 female, 1 male); "CALIF: Inyo Co., Eureka Valley, March 1978, Giuliani, Hardy, and Andrews/ Eureka Valley, transect anti-freeze pit trap, no. 8" [part of series, includes 8, 9, & two individuals from 20] (CSCA: 2 females, 2 males); "CALIF: Inyo Co., Eureka Valley, April 1978, Giuliani, Hardy, and Andrews/ Eureka Valley, transect anti-freeze pit trap, no. 7" [part of series, includes three individuals from 7 & two individuals from 8] (CSCA: 5 females); "CALIF: Inyo Co., Eureka Valley, March 1978, Giuliani, Hardy, and Andrews/ Eureka Valley, transect anti-freeze pit trap, no. 8" [part of series, includes 8, 9, & two individuals from 20] (CSCA: 2 females, 2 males); "El Cajon, San Diego Co., CA. 18 Feb 71/ Ex. Pyrus kawakami [non-focal]/ J.F. Johnson Coll." (CSCA: 1 female).

Distribution.

This species has been found in the desert and arid regions of Arizona and California (USA). It is likely that its range also includes Nevada (USA), northern Baja California and Sonora (Mexico), based on similarity in habitat to the currently known distribution (Fig. 50).

Natural history.

Associated with creosote bush ( Larrea tridentata [DC.] Coville [non-focal]; Zygophyllaceae [non-focal]) and evergreen pear ( Pyrus kawakami Tang S. Liu & H.J. Su [non-focal]; Rosaceae [non-focal]).