Poraniopsis inflatus inflatus is cream to bright orange with large white aboral spines. The five fat arms are up to 10 cm long and the arm-to-disc ratio ranges from 2.2 to 3.0. The aboral plates form an open mesh of large squarish areas occupied by numerous papulae. Prominent pointed spines occur at the junctions of the plates and a few smaller spines occur on secondary plates. Marginals are not readily distinguishable, because both series resemble the aboral plates and spines. Usually a row of smaller intermarginal spines are found on transverse plates between the two marginal series. Oral intermediates bear a few smaller, scattered spines between the inferomarginals and adambulacrals. The adambulacrals have one flat furrow spine and a similar flat or scoop-shaped spine on the oral surface. The mouth plates bear four marginal spines, the apical spine being largest and similar in size and shape to the adambulacral spines.
Similar SpeciesDifficult to confuse with any other species of sea star.