Eleodes (Melaneleodes) carbonarius knausii Blaisdell

Smith, Aaron D., Dornburg, Rebecca & Wheeler, Quentin D., 2014, Larvae of the genus Eleodes (Coleoptera, Tenebrionidae): matrix-based descriptions, cladistic analysis, and key to late instars, ZooKeys 415, pp. 217-268 : 241-243

Eleodes (Melaneleodes) carbonarius knausii Blaisdell Figs 3C , 6B , 9A , 11A , 12A

Material examined.

Larval Eleodes carbonarius specimens were reared from adults with the following collecting information: "USA: CO: Montezuma Co. / Ute RA off Hwy 160 / 37.3535, -108.44385 / 05 Jun 2011, ADSmith". A total of 129 eggs and larvae were reared and examined for this study, with 45 surviving until the 2nd instar or later. The following description is based on a detailed examination of five 8-11th instar specimens.

Description.

TL: 15.5-26 mm, HW: 2.3-3.0 mm, PL: 1.9-2.5 mm, PW: 3.0-3.5 mm.

Head. Prognathous, weakly flattened, narrower than prothorax; sides rounded, strongly constricted before occipital foramen; color ferruginous to dark brown, nearly as on body segments; minute punctation moderately dense dorsally. Epicranial stem approximately one-third head capsule length; frontal arms U-shaped, not obscured by sculpturing. Frons and dorsal portion of epicranial plates faintly rugose; lacking non-primary setae. Lateral portions of epicranial plates moderately setose; setae golden, erect, length equal to or longer than antennal segment 2; ventral portions of epicranial plates with a row of four to five long setae along anterior margin near buccal cavity and a patch of short setae medially forming a triangular pattern with its base near the anterior margin; two stemmata present on each plate, pigmented spots often faded. Clypeus trapezoidal; not swollen, moderately punctate, darker medially in basal half. Labrum not swollen, basal half more darkly pigmented; sides rounded; two transverse rows of six to seven erect setae present medially and subapically; anterior margin straight to weakly emarginate. Epipharynx ( Fig. 9A ) anterior setal row with six stout spiniform setae, anterolateral margins with micro-setation; six anterior sensory papillae present, arranged in two irregular diagonal rows; four subanterior sensory papillae present, arranged as a transverse row subtended by two spinose setae; eight posterior sensory papillae present, arranged in an irregular cluster. Tormae asymmetrical, left torma larger. Hypopharyngeal sclerome trapezoidal. Ligula with four long setae near apex. Gula distinct, trapezoidal, widest in basal half. Antenna three segmented, cylindrical; first segment longer than second.

Thorax. Dark brown to ferruginous dorsally and anterior to legs on prothoracic sternite, lighter brown on rest of sternites; distinct longitudinally striated band present along anterior fourth of prothoracic tergum; thin darkly sclerotized transverse line present on anterior fifth of meso- and metathoracic tergites; striated bands present along posterior 6th of all thoracic tergites, darker than rest of surface. Eight evenly arranged setae present on dorsal surface of each thoracic terga, lateral margins more densely setose. Prothoracic tergum wider than long, 1.5 × length of meso- or metaterga; lateral margins lacking pigmented band. Meso- and metaterga wider than long, lacking pigmented bands along lateral margins; mesothoracic spiracle simple, ovate, approximately 1.5 × size of abdominal spiracle; reduced metathoracic spiracle visible, less than one-fourth size of mesothoracic spiracle. Prothoracic leg slightly longer, much thicker than meso- and metathoracic legs; prothoracic tarsungulus strongly sclerotized, sickle-shaped; trochanter with two stout spines ventromedially, tibia with ventromedial row of three to four spines and four to five longer setae, tarsus with ventromedial row of five spines. Dorsal surface of protibia (at rest) with basal sclerotized band; dorsal surface of protarsus more sclerotized than ventral surface.

Abdomen. Tergites dark brown to ferruginous, concolorous or lightly lighter than tergites; longitudinally striated bands not visible on abdominal sternites, distinct on posterior 5th of terga 1-8. Abdominal sternite I sparsely clothed in long erect setae from anterior margin to near midline, abdominal segments 2-8 each with two sparse transverse bands of long erect setae, posterior margin of segment 8 denser setal band. Abdominal laterotergites concolorous with tergites, lacking distinct pigmented margins. Abdominal segment IX (pygidium) triangular in dorsal view, gradually reflexed to apex, sparsely clothed in short and mid length erect setae, apical two-thirds with faint maculations; marginal row of 18-20 socketed spines present apical half, apex not forming distinct sclerotized projection. Pygopods short, subconical, each with 9-12 erect spines.

Variation. Little variation was observed between specimens beyond the number of spines on the legs and pygidium, and the overall degree of sclerotization.

Diagnosis.

Eleodes carbonarius larvae can be separated from most currently known Eleodes species their darker dorsal coloration on all segments, the absence of pigmented bands along the lateral margins of the thoracic terga, and the lack of a distinct sclerotized tooth at the apex of the pygidium. They can be further distinguished from Eleodes anthracinus larvae as outlined in that species diagnosis.

Remarks.

Eleodes carbonarius adult morphology is notoriously variable across the species range and even within populations. Nine subspecies are currently recognized ( Triplehorn and Thomas 2011). The specimens examined were all reared from a few females of Eleodes carbonarius knausi Blaisdell collected at a single locality. Larval characters showed little variation; however, this may change as more specimens are reared from other localities and subspecies.

Figures

Figure 3. Dorsal habitus of four Eleodes species: A Eleodes (Litheleodes) extricatus B Eleodes (Melaneleodes) anthracinus C Eleodes (Melaneleodes) carbonarius D Eleodes (Tricheleodes) pilosus. Scale bar = 5 mm.

Figure 6. Lateral habitus of three Eleodes species: A Eleodes (Melaneleodes) anthracinus B Eleodes (Melaneleodes) carbonarius C Eleodes (Tricheleodes) pilosus. Scale bar = 5 mm.

Figure 9. Epipharynges of four Eleodes species: A Eleodes (Melaneleodes) carbonarius B Eleodes (Eleodes) armatus C Eleodes (Eleodes) hispilabris D Eleodes (Eleodes) tribulus. Scale bars = 1 mm.

Figure 11. Ligulas of three Eleodes species: A Eleodes (Melaneleodes) carbonarius B Eleodes (Eleodes) armatus C Eleodes (Promus) goryi. Scale bars = 200 µm.

Figure 12. Hypopharyngeal scleromes of two Eleodes species: A Eleodes (Melaneleodes) carbonarius B Eleodes (Litheleodes) extricatus. Scale bars = 200 µm.