(errant polychaete)

(sedentary polychaete)

PHYLUM ANNELIDA* (The segmented worms; traits from: Nielson 2012 p. 143-4, Ruppert et al. 2004 p. 420, 459, 482 and Brusca and Brusca 1990 p. 432. Tree from Andrade et al. 2015.

(oligochaete)

(leech)

     ===12$==(two+ clades)=== odd tube-building worms (Chaetopteridae, Oweniidae)
     |
     |                =====3= Errantia (active, highly mobile marine worms)
<<=1=|                |
     | =2=Polychaeta==|   =5= bone boring & parasitic Sedentaria (whalebone worms, myzostomids)
     | |               =4=|
     ==|                  =6= typical Sedentaria $$ (tube dwelling or burrowing worms)
       |
       |   =====8============ Oligochaeta (earthworms & relatives)
       |   |
       =7==|        ==10===== Acanthobdellida (primitive leech-like annelids)
           =====9===|
                    ==11===== Hirudinea (true leeches)

Back to Zool 250 tree for animal phyla or Protostomia

TRAITS SUPPORTING EACH CLADE (** plesiomorphic- a primitive state, not unique to clade) AND HIGHER TAXA:

1= ANNELIDA: a) many similar body segments each bearing a separate coelom** b) simple prostomium & pygidium** c) peristomium: a unique pre-segment surrounding the mouth d) no parapodia** e) multiciliated cells** f) chitinous setae in setal sacs** g) each seta secreted by a single cell h) 4 setal bundles per segment (2 dorsolateral, 2 ventrolateral) i) separate sexes, gametes from body wall (no permanent gonads)** j) segmented ventral nerve cord** k) closed circulatory system with capillaries and contractile vessels or hearts l) nephridia with nephrostome opening in segment anterior to nephridiopore m) trochophore larva** 2= POLYCHAETA a) extensive setae b) parapodia c) gametes from body wall (no permanent gonads)** d) complex prostomium e) nuchal organs (sensory) f) 1 pair pygidial setae 3= ERRANTIA: a) biramous parapodia well developed b) aciculum in each parapodial lobe c) dorsal and ventral cirri on parapodium d) 2 - 3 pairs of anatennae on prostomium e) pharynx with jaws (most) 4= SEDENTARIA a) parapodia reduced or absent** b) jaws usually absent 5: a) 1 modified body form; reduced segmentation 6$$: a) segments usually differ in form b) grooved feeding palps on prostomium

7= CLITELLATA: a) few setae b) simple prostomium** c) no parapodia** d) hermaphroditic e) clitellum (produces the cocoon in which eggs are laid) f) permanent gonads in a few segments g) trochophore larva lost 8= OLIGOCHAETA: a) calciferous glands of esophagus b) typhlosole (earthworms) 9= HIRUDINOMORPHA: a) ectoparasitic lifestyle b) single large coelom due to loss of septae between body segments c) fixed number of body segments d) setae restricted to a few anterior segments e) posterior (and often anterior) sucker f) dorsal anus anterior to posterior sucker g) superficial annuli in body wall h) unpaired, mid-ventral male gonopore 10= ACANTHOBDELLIDA: a) segmented coelom in anterior-most 5 segments (no anterior sucker)** b) prostomium and peristomium lost c) setae restricted to a few anterior segments** d) body of 29 segments 11= HIRUDINEA: a) well-developed anterior sucker b) body of 33 or 34 segments c) coelom unsegmented d) no setae e) unpaired female gonopore \ 12: a) tube-building habit (two separate basal clades)