Table 1 Characteristics of the giant peltospirids, Gigantopelta and Chrysomallon, in comparison to other species that retain plesiomorphic character states for the family Peltospiridae (Peltospira delicata) and the parent clade Neomphalina (Melanodrymia aurantica)
| Â | Neomphalina | |||||
|---|---|---|---|---|---|---|
| Â | Peltospiridae | |||||
Melanodrymia aurantica | Peltospira delicata | Gigantopelta chessoia | Chrysomallon squamiferum | |||
Body size | adult 2Â mm | adult 6Â mm | juvenile (2Â mm) | adult (50Â mm) | juvenile (2.2Â mm) | adult (45Â mm) |
Dermal armature | none | none | none | scales in few rows | dense and asymmetric scales | |
Nervous system | ganglionate | ganglionate | ganglionate | non-ganglionate | ||
Oesophageal gland | symmetrical foregut pouches without glandular material | small, symmetrical foregut glands | fused, enlarged gland, occupying 0.6% of visceral mass volume | fused, enlarged gland, increasing allometrically up to 9% of visceral mass volume | fused, enlarged gland, occupying 9% of visceral mass volume | fused, enlarged gland, increasing isometrically with growth |
Heart | heart not enlarged (ventricle 0.10Â mm in animal length 2.1Â mm) | heart not enlarged (ventricle 0.65Â mm in animal length 6Â mm) | heart greatly enlarged (ventricle 0.42Â mm in animal length 2.0Â mm) | heart greatly enlarged and muscular (ventricle 6Â mm) | heart greatly enlarged and muscular (ventricle 0.64Â mm in animal length 2.2Â mm) | heart greatly enlarged and muscular (ventricle 8Â mm) |
Blood sinuses | thin | thin | large, but few and fixed position | many large and mobile blood sinuses | ||
Reproduction | gonochoristic | gonochoristic | gonochoristic, fully developed gonad at body size 2.0Â mm | gonochoristic | no gonad present at body size 2.2Â mm | simultaneous hermaphrodite |