Araeoschizus antennatus

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Araeoschizus antennatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Beetle
Suborder: Polyphaga
Family: Tenebrionidae
Genus: Araeoschizus
Species: A. antennatus
Binomial name
Araeoschizus antennatus
Blaisdell, 1943

Diagnosis

Group III: The limbatus Blaisdell (1943) complex: Femora not toothed. Prothorax with longitudinal groove. Elytral interspaces with squamules

Superficially resembling limbatus Blaisdell; easily differentiated by the long head, more slender prothorax, the very narrow, rounded shoulders, narrow, elongated body. Dark brown ; shiny

Description

Head.- One-fourth longer than broad behind well elevated ocular lobe. Preocular angle evenly, continuously rounded with prominent frontal margin, with two small, well defined annules each side of middle; 2-4 short, sharply inwardly curving bristles. Anterior exterior angle of ocular lobe rounded , seemingly continuation of frontal margin ; rounded , angularly elevated . Sides slightly constricted at eye level ; occipital region broadly angularly rounded. Ocular ridge prominent, highly elevated , gradually shallo­wer behind eyes. Ocular groove shallow :portion anterior to eye shorter . Surface very fi­nely, unevenly granulate-punctate; each impression with a forwardly, slightly recum­bent , short, pale-yellow, club shaped squamule, squamules slightly longer, almost de­cumbent on frons. Posterior margin almost straight, with deep, broad triangular impres­sion on posterior half of well elevated vertex . Margin with erect squamules , which are denser on ocular lobe, more so on ocular ridge. Eyes small, elongate , strongly concave; with 19 facets dorsally , 5 ventrally . -Antennae reaching into posterior fourth of protho­rax. Joints well separated ; 2 longest , broadest, narrower at base; 1 nearly as broad as 2, shorter; 3 broadly rounded at anterior, narrow at posterior end, one-third shorter than 2 ; 4-9 about even (however 4-5 slightly broader); 10 slightly impressed laterally , about as wide as 3; 11 short, about half size of 10. Joints 1-6 with longer erect squamules , from 7 on squamules slightly narrower , shorter ; on 10 hairlike, on 11 more so. Squamules on jo­ints 3-8 on anterior half of each joint; on 9-10 surface uniformly squamulose. Prothorax. - Almost as long as wide on broadest anterior half. Somewhat darker brown than head, elytra; very coarsely granulose. Frontal, posterior margins straight ; la­ter more densely squamulose. Sides broadly rounded behind slightly rounded anterior angle, then gradually constricted towards middle; posterior third nearly parallel, with erect, sparsely spaced pale squamules. Longitudinal groove narrower at middle ; deepest at posterior fourth ; not squamulose. Two longitudinal ridges well elevated, with row of dense, erect, darker yellow squamules; slightly constricted about middle. Surface be­tween ridges, exterior margins of prothorax very densely covered with short, erect squa­mules. Dense, golden -yellow multiple row of squamules on posterior margin, separated in middle, leaning toward ends of two ridges, not forming tufts . Elytra. -About one-fourth longer than head, prothorax combined; slender. Ante­rior margin straight, short , same width as posterior margin of prothorax. Scutellum sharply pointed, well defined. Shoulder narrowly rounded , almost same angle as poste­rior of abdomen ; sides at middle-third almost parallel. Primary cordae prominent, shar­ply elevated with erect, slightly curved club-shaped squamules, somewhat recumbent in posterior fourth. Secondary corda 1 slightly elevated, others not; squamules on secon­dary row, sutural lines sparse; distance between squamules much less than length of squamules; not entire, longest, 4 shortest . Puncture lines prominent, punctures round, deep, with sharp edges; distance between less than half diameter of puncture; surf ace between very finely granulose. Underside. Head. - Surface very coarsely granulose; hour-glass shaped gular groove deep,broad, its margins distinctly squamulose ; surface finely punctulate; basal groove of post gena deep, broad. Mentum slightly broader than long, lighter brown ; densely covered with outwardly projecting, hair-like squamules ; sides, front continuously evenly roun­ded . Terminal joint of maxilla shorter, narrower than proceeding; pale yellowish-brown. Post genal process sharp, prominent , interior base slightly carinate, margin between straight; surface of process, margin of plate evenly densely squamulose; genal area spar­ sely covered with club-shaped, forwardly recumbent pale squamules, which are slightly longer both sides of posterior end of gular impression. Prothorax. -Surface granulose; only area anterior to coxae, prominent prosternal ridge, margin of prosternal process sparsely squamulose. Prosternal ridge slightly eleva­ted, Y-shaped at anterior end ; posterior end sharply constricted, more elevated be­tween coxae; prosternal process broadly rounded , narrowly-pointedly reaching posterior margin of prothorax. . Hindbody . - Surface with large, flat, densely spaced punctures; each punctu re with a narrow, decumbent squamules which is slightly longer than diameter of puncture. Size of punctures for abdominal segment 2 gradually decreases posteriorly; those on seg­ment 5 about one-third of those on 1. Mesosternum short, mesosternal process narrow, slightly broader, flatly rounded posteriorly. Metasternum with narrowly rounded meta­sternal process, which is slightly more elevated than posterior margin on opposite side. Segment 1 with broad , sharply forwardly pointing, triangularly shaped process between posterior coxae, which is blackish-brown, impressed in middle. Segments as above. Legs. - Femorae of uniform thickness; posterior pair longest; middle pair slightly smaller than anterior. Sides sparsely, edges densely covered with short, recumbent, club-shaped pale squamules. Tibiae more squamulose than femora, with distinct tibial collar consisting of row of short, erect, golden-yellow spine-lie squamules. Tarsi densely squamulose throughout. Length : 4.0-4.2 mm.

Distribution

Mexico: Baja California (type) Holotype :Mexico, 10 miles S of Punta Prieta, Baja California Norte, June 21, 1938, Michelbacher and Ross Collectors (CAS). Additional specimens :Mexico, 13 mi . E of El Rosario, Baja California Norte, D. Q. Cavagnaro, G. E. & E. S. Ross, and V. L. Vesterby Collectors, 2 specimens (CAS). Santa Ynez, Baja California Norte, April 11, 1978, H. Clark Collector , 1 specimen (CID).

Specimens from El Rosario and Santa Ynez (some 60 mi. apart ; 120 mi. North of type locality) slightly differ from the holotype. However, insufficient material makes it unjustified to handle those as a subspecies to antennatus.The differences may be summa­rized as follows : Slightly more slender. Head narrower posteriorly . Occipital impression broad , flat. Ocular groove posterior to eye flat, not outlined . Ocular ridge shallow ;with erect longer squamules . Eye large, 18 facets dorsally, 5 ventrally . Antennae very densely covered with semierect long squamules . Surface of head densely punctured with smaller punctures than prothorax. Prothorax similar to antennatus , except squamules on longitudinal median ridges (creating groove), and along margins of prothorax, goldish-yellow, long, erect. Elytral costae with denser row of longer erect squamules. Sutural line very narrow, not grooved, tightly fused , two rows of erect squamules sparsely spaced, short, same size shape as on secondary rows.

Biology

REFERENCES

  • Blaisdell, R.E.: 1943. Contribution Toward the Knowledge of the Insect Fauna of Lower California. No. 7 Coleoptera, Tenebrionidae. -- Proc. Calif. Acad. Sci., 24:171-288, p1. 10 and 11 (pp. 214-216, p1. 11).
  • Clark, W. 1991, Location of holotype of Araeoschizus antennatus Blaisdelli Papp (Coleoptera, Tenebrionidae). Pan-Pacific Entomologist. vol. 67 (1): 73.
  • Papp,C.S. 1981. Revision of the genus Araeoschizus LeConte (Coleoptera: Tenebrionidae), Entomologische Arbeiten aus dem Museum G. Frey 29: 273-420.
  • Papp, C.S. 2001. Two new Araeoschizus species from the Vizcaino Peninsula of Baja California sur, Mexico and discussion of species groups: (Coleoptera: Tenebrionidae). Journal of the Idaho Academy of Science.37 (1):