MYRIAPODS CENTIPEDES ▸ Subphylum Myriapoda ▸ Class Chilopoda ▸ Two tagmata: head and trunk ▸ tracheae with spiracles ▸ Maxillipeds CHAPTER 14 MYRIAPODA Scolopendra heros, Texas up to 9 inches in length MYRIAPODS MILLIPEDES ▸ Class Diplopoda — ▸ Two tagmata: head (with ocelli) and trunk ▸ tracheae ▸ Detritivores or herbivores ▸ some defensively toxic House centipede -- introduced species MYRIAPODS OTHER MYRIAPODS ▸ Classes Pauropoda and Symphyla— ▸ Centipede-like in appearance ▸ limbs on each segment ▸ soft-bodied symphilid phylogeny of myriapoda pauropod from Edgecombe, G. D. and Giribet, G., 2002 MANDIBULATA? CURRENT PHYLOGENETIC IDEAS ARTHROPODA ▸ Clade Mandibulata Hexapoda (subphylum?) ▸ Myriapoda Branchiopoda PANCRUSTACEA ▸ Pancrustacea Malacostraca ▸ Hexapods? Myriapoda ▸ Regier, et al (2010) MANDIBULATA CHAPTER 14, PART 3 ▸ long branch attraction? Chelicerata ▸ long branches may show Onychophora erroneous affinities ▸ may increase likelihood of Tardigrada convergences CRUSTACEA Nemata adapted from Rota-Stabelli, et al (2010) CRUSTACEANS CRUSTACEANS ▸ Anatomy PANCRUSTACEA ▸ Three tagmata: head, thorax, abdomen ▸ Subphylum Pancrustacea (crustacea)— ▸ Heavily calcified exoskeleton ▸ aquatic, terrestrial, many are planktonic ▸ carapace ▸ usually dioecious, sometimes monoecious, sometimes ▸ Two pairs of antennae parthenogenic Cephalothorax ▸ nauplius antennule ▸ carapace three pairs appendages, Abdomen ▸ first antennae antenna ▸ second antennae pleopods ▸ mandibles cheliped walking legs (pereopods) ▸ medial eye 1 ▸ zoea 2 5 3 4 CRUSTACEANS CRUSTACEANS ▸ Ancestrally biramous appendages ▸ open circulatory system like all arthropods ▸ Basal protopod ▸ hemolymph ▸ lateral exopod ▸ hemocyanin or hemoglobin ▸ medial endopod branches ▸ arteries, hemocoels, venus sinuses, ostia, heart ▸ epipod ▸ coelom greatly reduced ▸ gills for gas exchange PROTOPOD body wall heart branchiostegite EXOPOD stomach gonad digestive gland ENDOPOD green gland CRUSTACEANS PANCRUSTACEA ▸ digestion end sac carapace ▸ cardiac stomach, pyloric stomach TAXONOMY ▸ excretion ▸ CLASS REMIPEDIA antennule ▸ gills trunk labyrinth ▸ many ancestral antenna appendages ▸ green gland nephridial canal features bladder ▸ CLASS CEPHALOCARIDA ▸ also lots of heart plesiomorphies stomach gonad ▸ monoecious digestive gland green gland PANCRUSTACEA PANCRUSTACEA ▸ CLASS OSTRACODA ▸ CLASS BRANCHIOPODA ▸ phyllopodia ▸ Mostly freshwater forms ▸ Order Cladocera [Diplostraca] PANCRUSTACEA ▸ CLASS COPEPODA ▸ Very abundant PANCRUSTACEA PANCRUSTACEA thoracic appendages (cirri) ▸ CLASS PENTASTOMIDA ▸ CLASS CIRRIPEDIA tergum ▸ formerly placed in a separate phylum ▸ no chitinous exoskeleton; scutum ▸ calcareous plates ▸ Filter feed with cirri antennules PANCRUSTACEA PANCRUSTACEA ▸ CLASS MALACOSTRACA ▸ limbs ▸ most of the large crustaceans ▸ 8-head(feeding/sensory), 5-thorax(walking), 6- abdomen(swim/respire/reprod.) ▸ gills ▸ branchiostegite “shield” PANCRUSTACEA PANCRUSTACEA ▸ Pillbugs -- “rollypolly” ▸ pseudotracheae PHYLOGENY ▸ Crustacean phylogeny ▸ lots of disagreement/questions SOWBUG ▸ insects --> xenocarida ▸ just fancy crustaceans? PILLBUG GIANT MARINE ISOPOD Bjoern M. von Reumont et al. Mol Biol Evol 2012;29:1031-1045 .