Cordielytrum adustum, Whorrall & Philips, 2021

Whorrall, Kyle & Philips, Keith, 2021, Six new species of spider beetles (Coleoptera: Ptinidae) in the genus Cordielytrum Philips, Zootaxa 5040 (3), pp. 414-427 : 422

Cordielytrum adustum , sp. n.

( Fig. 7 )

Holotype: Arequipa Region, nr. Pescadores , 17–22.VI.2019 S16.3876° W73.2588° 19m riparian veg, dung pitfalls K.A.Whorrall & T. K.Philips . Holotype has been deposited in MUSM . Paratype (1): Same data as holotype. Paratype will be deposited in TKPC .

Diagnosis: This species is distinguished from most congeners by the rough, disheveled appearance of its vestiture, and its unique scoop-shaped scales. The only two specimens are of notably small size, though this may not be representative of the true size variation within the species. It can be distinguished from C. fimbriatum ( Fig. 5 ) and C. obscurum ( Fig. 6 ) by the short erect filiform setae covering its body, its more convex shape, the dark bands on the carinae of its elytra, and the relatively large depressions in its elytral setation. The species can be distinguished from C. inca ( Fig. 4 ) by the more rounded pronotum, larger scale size relative to the body, and much shorter setae at the humeral angles of the elytra.

Description. Body very small, ovate, convex; mottled reddish brown with a slight sheen. Length (anterior of pronotum to apex of elytra) 1.81 mm.

Head completely covered with depressed, light tan, ovoid scales; pronounced superantennal carinae; antennae stout, antennomeres densely covered in scales, setae increasingly fine toward apex, antennomeres 1–4 and 11 longer than wide, others subequal; clypeus distinct; labrum with short erect orange setae apically; frons with elongate ligulate scales pointing toward middle, especially prominent toward apex.

Pronotum covered with densely matted setae, relatively few short, erect setae protruding from deep cavities within matted setation; anteriorly depressed, especially laterally; medial cavity shallow broad, extending over half total length of pronotum, border well-defined except at middle anterior and posterior; two posterolateral cavities on each side deep and distinct.

Elytra: Setation mottled tan and dark brown, background color reddish brown; surface covered in triangular scoop-shaped setae; basal 1/3 of anterolateral margin with row of relatively short bristly setae; five low longitudinal carinae extending length of each elytron, including one at suture, each carina with one row of very short truncate setae; ~3 rows of deep, open depressions between carinae.

Ventral Surface: Ventral part of pro-, meso, and metathorax, legs, and abdominal ventrites with scales similar to elytra.

Etymology: The name “adustum” is from the Latin word for singed, referring to the darkened appearance of the elytral pattern.

Figures

FIGURE 4. Cordielytrum inca. A Dorsal habitus, B ventral sclerites, C lateral view, D frontal close-up. Scale bars: 1.0 mm (A, C), 0.5 mm (B, D).

FIGURE 5. Cordielytrum fimbriatum. A Dorsal habitus, B ventral sclerites, C lateral view, D frontal close-up. Scale bars: 1.0 mm (A, C), 0.5 mm (B, D).

FIGURE 6. Cordielytrum obscurum. A Dorsal habitus, B ventral sclerites, C lateral view, D frontal close-up. Scale bars: 1.0 mm (A, C), 0.5 mm (B, D).

FIGURE 7. Cordielytrum adustum. A Dorsal habitus, B ventral sclerites, C lateral view, D frontal close-up. Scale bars: 0.5 mm (A, C), 0.25 mm (B, D).