. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. "Regular1 Echinoids Holectypoids Spatangoids, Holasteroids Cassiduloids Clypeasteroids General Habitat Preferences: Hard substrates. Fine sands or muds Coarse sands. Fine, clean 1. Greatly expanded fields of oral accessory podia. 2. Phyllodes greatly reduced, particle picking with accessories only. f Podial particle picking with botrTl I phyllopodia & accessory podia. J (Podial particle picking with phyllopodia only) Figure 6. Phylogeny of podial particle picking in the major extant clades of Echinoidea. Arr
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. "Regular1 Echinoids Holectypoids Spatangoids, Holasteroids Cassiduloids Clypeasteroids General Habitat Preferences: Hard substrates. Fine sands or muds Coarse sands. Fine, clean 1. Greatly expanded fields of oral accessory podia. 2. Phyllodes greatly reduced, particle picking with accessories only. f Podial particle picking with botrTl I phyllopodia & accessory podia. J (Podial particle picking with phyllopodia only) Figure 6. Phylogeny of podial particle picking in the major extant clades of Echinoidea. Arrows indi- cate positions of events in evolution of particle picking listed within boxes. In small figures of echinoids, mouth and anus are shaded, phyllodes are shown in solid black, accessory podial pores are indicated by dots in ambulacra, "L" indicates taxa with an Aristotle's lantern in the adult. Phylogeny after Smith (1984). In most clypeasteroids there is a small set of slightly enlarged podia [which Mooi (1986b) called "large food groove podia"] adjacent to the peristome, but just distal to the buccal podia. These podia are similar in overall morphology and histology to other food groove podia, but are about twice their size. Large food groove podia are not involved in particle collection; rather, they help guide strings of aggregated food material into the mouth. Phelan (1977) suggested that the phyllodes of cassidu- loids were homologous with the entire podial field on the oral surface of clypeasteroids. However, accessory podia are modified into phyllopodia during the ontogeny of cassiduloids, a process also responsible for the differen- tiation of the large food groove podia of clypeasteroids. The rest of the accessory podia in the expansive ambula- cral fields of clypeasteroids do not undergo this modifi- cation. These developmental patterns, as well as the overall anatomy and arrangement of the phyllopodia in cassiduloids, indicate that their p
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
