Pseudacris crucifer (Weid, 1838)
Key Characters: Large toe pads; dark “X” on back; dark spot or narrow bar between eyes.
Similar Species: Gray treefrogs, Bird-voiced treefrog. See Key to Illinois Frogs & Toads for help with identification.
Subspecies: Formerly two subspecies were recognized, but they were rejected by Austin et al. (2002, Mol. Phylogenet. Evol., 25: 316-329).
Description: Small (up to 3.5 cm SVL) tan, pink, brown, or gray frog with dark diagonal lines suggesting an “X” on back. Belly white, sometimes with dark flecks. Snout projects beyond lower jaw when viewed in profile. No light spot under eye, or light stripe on upper jaw. Male with folded skin under throat indicating vocal pouch.
Habitat: Mesic forests, on trees, shrubs, and herbaceous plants. Most often seen around woodland pools in spring; seldom seen outside breeding season. Breeds in ponds and water-filled depressions in upland forest.
Natural History: Aptly named because it is one of first frogs to call each spring. Diet consists of small insects and spiders. Mates late February through May; some males call in autumn. Call is a soft, clear, ascending “peeeep” repeated about once each second and heard both day and night. Males commonly call in alternating duets or trios while perched in vegetation over water or on surface of water. Several hundred eggs per female, attached singly to sticks or leaf petioles, hatch in a few days, and tadpoles transform in about two months.
Distribution Notes: Found throughout much of the state, except in the Grand Prairie.
Status: Locally common.
Etymology: Pseudacris – pseudos (Greek) meaning lie; -akris (Greek) meaning locust; crucifer – crucis (Latin) meaning cross; ifer (Latin) meaning bearer.
Original Description: Wied, Maximilian, Prinz zu. 1838. Reise in das innere Nord-Amerikain den Jahren 1832 bis 1834. J. Hoelscher, Coblenz. Vol. 1. 653 pp.
Type Specimen: Unknown.
Type Locality: “Cantonment Leavenworth”
Original Name: Hyla crucifer
Nomenclatural History: Transferred to Pseudacris by Hedges (Hedges, S. B. 1986. An electrophoretic analysis of Holarctic hylid frog evolution. Systematic Zoology 35: 1–21). Hyla pickeringii Holbrook, 1839 (Holbrook, J. E. 1839 “1836”. North American Herpetology; or Description of the Reptiles Inhabiting the United States. First Edition. Volume 1 (Expanded second version). Philadelphia: J. Dobson) is a junior synonym used in the Illinois herpetological literature. Placed in synonymy by Cope (Cope, E. D. 1889. Batrachia of North America. Bulletin of the United States National Museum 34: 5–525).