Platydracus exulans is distinguished from congeners by its bronze-green metallic head and pronotum (Fig. 11.10.1), and the unevenly spaced pronotal punctures (Fig. 7.2.1). The only other Platydracus with uneven pronotal punctures is P. praelongus, however, P. exulans differs by the narrower median impunctate area of the pronotum (Fig. 7.5.2) and by general habitus. The metallic colour gives it some similarity to P. viridanus but the latter has evenly spaced pronotal punctures and a different abdominal pubescence pattern.

Platydracus exulans is an eastern species, occurring as far north as Ontario and extending southwest to Louisiana. Its range in ECAS is given by Map 14. This species is newly recorded from Michigan, Ohio, and Pennsylvania. It was reported from Québec by Downie and Arnett (1996) without data, but we have seen no specimens from that province and this record is probably based on a misidentified specimen.

UNITED STATES: MI: Ingham Co., East Lansing, 42.7333 -84.4833, Date Unknown, C.F.B, 1 (FMNH). OH: Hamilton Co., Cincinnati, 39.1 -84.52, V-1934, 1 (UMMZ). Hocking Co., Ash Cave Area, 39.4003 -82.5384,   1-V-1986, bark, R.L. Aalbu, 1 (FMNH). PA: Delaware Co., Manoa, 40 -75.3, IV-1946, E.J. Ford, 1 (BPBM). Westmoreland Co., Jeannette, 40.3333 -79.6166, 14-IV-1931, 1 (FMNH); 16-IV-1931, 2 (AMNH), 1 (FMNH).

Eastern Canada: ON
Adjacent U.S.A: IN, MI, NY, OH, PA

Platydracus exulans has been collected from late March to late June, with the majority of records in April and May.   

Most available specimens with collection data are from dung or dung-baited pitfall traps in mixed oak-pine forest. However, Newton (1973) reported it from carrion, including opossum, chicken, and rabbit. Watson (2004) found this species in Louisiana on carcasses of alligator, bear, deer, and pig during the winter and spring. Platydracus exulans was found most frequently on pig carcasses in the advanced to dry stage of decay (Watson 2004). Newton (1973) suggested that the relatively early season occurrence and scant appearance at baits may indicate that P. exulans dwells primarily within vertebrate nests or a similar microhabitat.

This species has been collected twice in Ontario, both times in the same location near Ottawa but forty-four years apart. Further collecting is needed to determine whether the Canadian specimens of P. exulans represent sporadic migrants or part of a stable Canadian population.