Anatomy of Ectonocryptoides (Scolopocryptopidae: Ectonocryptopinae) and the phylogeny of blind Scolopendromorpha (Chilopoda)

摘要

The chilopod subfamily Ectonocryptopinae (Scolopocryptopidae) comprises rarely-encountered, small-bodied scolopendromorphs known only from Mexico and Belize. Three species have been described, one in Ectonocryptops Crabill, 1977, and two in Ectonocryptoides Shelley & Mercurio, 2005. External characters ally this clade with the speciose Neotropical subfamily Newportiinae. Scanning electron microscopic documentation of the mouthparts, peristomatic structures and foregut in Ectonocryptoides quadrimeropus Shelley and Mercurio, 2005, together with new data for Newportia, enable analysis of ectonocryptopine relationships based on the current character set for scolopendromorph phylogeny. A distinctive “pineapple-shaped” gizzard projection strengthens the alliance between Ectonocryptopinae and Newportiinae, which group together as a well-supported clade that is stable under equal and implied weights. In all shortest cladograms across a range of character weights, Ectonocryptopinae nests within Newportiinae. Scolopocryptopidae (sensu Shelley (2002)), which groups species with 23 trunk segments, kinked gizzard projections, and a pectinate second maxillary claw, is monophyletic in most cladograms under equal weights and is consistently monophyletic when homoplastic characters are down-weighted; the alternative set of equally-weighted cladograms resolves the 21-segmented Plutoniuminae within Scolopocryptopidae. Ectonocryptoides quadrimeropus displays pore fields on the ventral surfaces of the swollen tibia and first tarsus of the ultimate leg that evidently represent glandular openings. Observations on Ectonocryptoides quadrimeropus and Newportia monticola suggest that new systematic characters for Scolopocryptopidae can be found in the specialised apical setae on the terminal antennomere.