Abstract

Scolopendromorpha is unique among Chilopoda in the differentiation of a structurally complex gizzard at the posterior end of the foregut. Classical descriptions indicate major morphological differences between the gizzards of a few documented members of the main groups, Scolopendridae, Cryptopidae and Scolopocryptopidae. A survey of gizzard anatomy for 30 species by light and scanning electron microscopy introduces 13 characters of the foregut to a matrix including 67 additional morphological characters for inferring scolopendromorph interrelationships. A sieve-type gizzard shared by Cryptopidae and Scolopocryptopidae supports a single origin of blindness in Scolopendromorpha; monophyly of blind lineages emerges as equally parsimonious to the paraphylyetic arrangement favoured by previous analysis without gizzard characters. Unique substructures of the sieve projections provide new support for the monophyly of Cryptopidae, Plutoniuminae, and the traditional grouping of Scolopocryptopidae. Comparison with the states in Scolopendridae favours a new homology assumption for parts of the foregut, which recognizes the sieve in blind scolopendromorphs as homologous to the posterior part of the gizzard in Scolopendridae that variably bears circlets of short lobes. The plicae in front of the sieve lack cuticular trichomes, whereas most scolopendrids show longitudinal rows of spines or spine-bearing plates in the corresponding region. The basal resolution of Asanadini and Arrhabdotini within the Scolopendridae is reinforced by spiniferous scales on the gizzard's plicae that are uniquely shared by Otostigmini and Scolopendrini.