Eleodes (Litheleodes) extricatus (Say, 1823)

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 : 235-237

Eleodes (Litheleodes) extricatus (Say, 1823) Figs 3A , 5C , 7B , 10A , 12B , 13B

Material examined.

Larval Eleodes extricatus specimens were reared from adults with the following collecting information: "USA: TX: El Paso County / El Paso, sand dunes off / Hwy 180/Montana Ave. / N31.82327, W106.13234 / 21-22.VIII.2010, ADSmith", "USA: Arizona: Navajo Co. / dunes ~4mi N Chilchinbito / off route 59, el. 1738m / N36.58143, W110.06973 / 26.August.2010, ADSmith", "USA: AZ: Graham Co. / Pinaleño Mnts, Hospital Flat Camp / N32°39 ’58.0”, W109°52 ’30.9” / el.9000' 22.Aug.2010 / ADSmith", "USA: Arizona: Gila County / E. Verde River off NF-272 / N34.303, W111.3496 / 27.August.2010, ADSmith". Approximately 219 eggs and larvae were reared and examined for this study, with 150 surviving until the second instar or beyond. The following description is based on a detailed examination of thirteen 8-11th instar specimens.

Description.

Measurements: TL: 15.4-33.3 mm, PL: 2.4-3.8 mm, PW: 2.2-3.8 mm, HW: 2.0-3.0 mm.

Head. Prognathous or weakly declined; weakly dorsoventrally flattened; width nearly equal to prothorax; sides rounded; strongly constricted before occipital foramen; color light tan, same or nearly the same as body segments; punctation minute, dense, separated by 1-2 puncture diameters. Epicranial suture stem length approximately one-third head capsule length; frontal arms sinuate, not obscured by sculpturing. Frons faintly rugose. Epicranial plates faintly rugose dorsally; lateral portions moderately setose; ventral portion of each plate with row of six or more long setae along anterior margin near buccal cavity confluent with setae on lateral portions of plates and a patch of short setae medially, forming a triangular pattern with its base near the anterior margin. Two stemmata present on each epicranial plate, pigmented spots often faded. Clypeus trapezoidal, swollen or not, unicolorous, minutely punctate, punctation dense, separated by 1-2 puncture diameters. Labrum swollen, sides rounded, basal half more darkly pigmented, medial setal row with six to seven erect setae, subapical setal row with six to seven erect setae, anterior margin straight to weakly emarginate. Epipharynx ( Fig. 10A ) anterior setal row with six stout spiniform setae, anterolateral margins with micro-setation; six anterior sensory papillae present, arranged in two irregular 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 symmetrical or weakly asymmetrical with left torma smaller. Ligula apex densely microsetose, two long subapical setae present ventrally. Hypopharyngeal sclerome pentagonal, tricuspidate. Gula distinct, trapezoidal, widest in basal half, length less than maximum width. Antenna three segmented, cylindrical, first segment longer than second.

Thorax. Thoracic tergites light tan, prothoracic sternite anterior to legs ferruginous, thoracic sternites posterior to prolegs light brown. Prothoracic tergum subquadrate, 1.5 × length of meso- or metaterga; anterior transverse striated band present, darker than protergal disc; lateral margins with distinct granulated band, darker than protergal disc. Posterior transverse striated band present on all thoracic tergites, unicolorous brown. Meso- and metathoracic tergites wider than long, each with a heavily sclerotized transverse line present on anterior fifth. Thoracic tergites sparsely setose on dorsal surfaces, lateral margins more densely setose. Mesothoracic spiracle simple, ovate, approximately 1.5 × size of abdominal spiracles; reduced metathoracic spiracle visible, less than one-fourth size of mesothoracic spiracle. Legs. Prothoracic leg slightly longer, much thicker than meso- and metathoracic legs; prothoracic tarsungulus strongly sclerotized, sickle-shaped; prothoracic trochanter with two stout ventromedially spines; prothoracic femur with ventromedial row of two spines and three to five longer setae, dorsal surface with faintly indicated basal sclerotized band; prothoracic tibia with ventromedial row of three to four spines or spinose setae, dorsal surface slightly more sclerotized than ventral surface. Mesotibia with four to five ventromedial spines.

Abdomen. Abdominal tergites and sternites light tan, with slightly darker transverse striated bands present along posterior margins of segments I-VIII, forming near contiguous unicolorous band around segments. Abdominal sternite I sparsely clothed in long erect setae from anterior margin to near midline. Abdominal laterotergites with lateral margins distinctly pigmented. Abdominal segment IX (pygidium) triangular in dorsal view, gradually reflexed to apex, urogomphi absent, apex lacking a distinct tooth, sparsely clothed in short and mid length erect setae, sclerotized uniformly throughout, lacking maculations; marginal row of 17-23 socketed spines present, arranged as single row around posterior two-thirds to one half of segment. Abdominal sternites I-VIII lacking longitudinal tomentose bands along lateral margins. Pygopods short, subconical, each with 11-15 erect setae.

Diagnosis.

Eleodes extricatus larvae can be separated from the other currently known Eleodes species based on the pentagonal hypopharyngeal sclerome, small or absent apical tooth on the pygidium, lateral margins of prothoracic tergum with a distinct granulated band, and having antennal segment I longer than antennal segment II.

Remarks.

Eleodes extricatus is a widespread species found on dunes and at high elevations. Specimens from Arizona and Texas showed no population differences in the larval stage. Adults varied in the presence or prominence of muricate tubercles on the elytra.

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 5. Lateral habitus of three Eleodes species: A Eleodes (Eleodes) caudiferus B Eleodes (Eleodes) tribulus C Eleodes (Litheleodes) extricatus. Scale bar = 5 mm.

Figure 7. Lateral habitus of the head and thoracic segments of three Eleodes species: A Eleodes (Melaneleodes) anthracinus B Eleodes (Litheleodes) extricatus C Eleodes (Promus) subnitens. Scale bar = 5 mm.

Figure 10. Epipharynges of four Eleodes species: A Eleodes (Litheleodes) extricatus B Eleodes (Promus) goryi C Eleodes (Promus) subnitens D Eleodes (Tricheleodes) pilosus. Scale bars = 1 mm.

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

Figure 13. Abdominal sternites I and II for two Eleodes species: A Eleodes (Eleodes) caudiferus B Eleodes (Litheleodes) extricatus. Scale bars = 1 mm.