No species of Cherax has been considered endemic to wet upland or highland areas before it was discovered; most previous records were from elevations less than 400 meters.

It also has several morphological features unique to the genus, and does not appear closely related to any extant species, suggesting a long period of geographic isolation.

The lateral carinae are moderately developed, commencing at the base of the rostrum, terminating at the acumen, without tubercles or spines.

The epistome (plate in front of the mouth) is strongly concave at the middle and bristly anteriorly with distinct tubercles laterally.

The branchial formula is typical for the genus with the posterior arthrobranch (gill attached to the articular membrane between the body and the basal joint of a leg) above P4 reduced.

Pleurocoxal (of the first segment of the leg) lappets are well-developed and are fringed with long, plumose setae (hair-like projections).

The sternal keel (long ridge that runs lengthwise along the top of the head) is sharp posteriorly, more rounded anteriorly, and bristly laterally.

The carpus (third segment from the distal end of the leg) bears a large, broad, hook-shaped mesial spine (missing on left cheliped).

The angle of the distoventral or ventromesial condyle (a heavily sclerotized projection of the mandible's dorsal surface) is not produced into a spine or tubercle.

This species is found in the upper Tully River and its tributary, O’Leary Creek; above Koombooloomba Dam, at 720–750 m altitude; and the Cardwell Range.

The following unique features suggest a long period of geographic isolation: With regard to the last character, inflated branchiostegisites and narrow areolae are generally correlated with the enlargement of the branchial chambers and increased surface area of gills.

The relatively small branchial chambers of C. parvus may reflect its preference for cool, well-oxygenated, rainforest streams.

C. parvus, however, has two well-defined uncalcified patches on the first cheliped of mature males and is clearly allied to the quadricarinatus species-group.