John Duncan 1/30/13 Ichthyology Order Assignment Polypteriformes

John Duncan
Order Assignment
Polypteriformes- (Greek poly-, ‘many’: Latin pteron-, ‘fin’ or ‘wing’).
Taxonomy: -Class: Actinopterygii – ray finned fishes
-Order: Polypteriformes – Reedfish and Ropefish
-Family: Polypteridae
-2 Genera, 10 species
Description: elongated or anguilliform fish. Romboid shaped ganoid scales. Defining
feature is a row of ‘finlets’ along the dorsal region of fish. Each dorsal finlet consists of
one spine followed by a fan of rays. Numbers of finlets can range from 5-18 in number.
Ray pectoral fins, and symmetric caudal fin that often appears to merge into rear dorsal
finlets. Respiration occurs through both gills and a bi-lobed swim bladder that can act as
a lung when needed. The external gills disappear in adults. Wide range in sizes, most
being under 30cm but ranging up to 90cm.
Habitat: There is variation between species within this order, but they are typically
demersal (Near-bottom dwelling). They tend to live in river basins or in flooded regions.
When living in lakes they tend to stay towards the river entrances and deltas.
Distribution: They live in the inland waterways of Africa with most species found in the
Zaire River basin. Additionally there are some species in the Congo River basin and
Lake Tanganyika.
Ecology and Life History: Polypteriformes are non-brood-guarding species. They are
carnivorous. Most species are predominantly piscovorous, but some (such as Polypterus
endlicherii) also are known to eat snails and small crustaceans.
Additional Details: These fish tend to have a very ancient look to their appearance. The
elongated body, dorsal finlets that merge into the caudal fin, and low, slung jaw give it a
predatory, old-world bearing.
Recent Research:
Suzuki, D., M.C. Brandley and M. Tokita, 2010. The mitochondrial phylogeny of an
ancient lineage ray-finned fishes (Polypteridae) with implications for the evolution of
body elongation, pelvic fin loss, and craniofacial morphology in Osteichtyes. BMC
Evolutionary Biology 10:1-12.
References: Fishbase: Order Polypteriformes, Family Polypteridae, Species Polypterus
endlicherii and Polyperus congicus.