Palæos:		Procoelomates
INVERTEBRATES		Molluscomorpha

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Molluscomorpha - Proto-molluscs

Status The molluscomorpha are the (largely theoretical) line between Lophotrochozoa and Mollusca.  Nearly everyone's best guess at present is that the Halkeriida are very close to that line.  At the moment, we cover nothing which actually falls between Halkeriida and Mollusca, so this entry is essentially a placeholder, eventually to be filled by Kimberella, Hyolitha, and probably sipunculid worms.  A cladogram -- no more speculative than most -- is included below. Our working cladogram looks like this: Lophotrochozoa |--Halkeriida `--+--BRACHIOPODA `--MOLLUSCOMORPHA | MOLLUSCA

 

Halkieria evangelista
length about 3.7 cm

This cladogram combines Conway Morris 1993, Conway Morris 1998, and Runnegar 2002. Both the Order Halkeriida and the Class Coeloscleritophora are considered paraphyletic grades.

<==o LOPHOTROCHOZOA
   `--o COELOSCLERITOPHORA (paraphyletic)
      |--+-- †Chancelloriida
      |  `-- †Sachitida
      `--+-- †Siphogonuchitida
         `--o †Halkieriida (paraphyletic)
            |-- †Halkeria evangelista
            |--o "MOLLUSCOMORPHA"
            |  |?- †Kimberella
            |  `--+?- †Tullimonsterida
            |     |--o Mollusca
            |     |  `--+-- SOLENOGASTRES
            |     |     `--+-- †Acaenoplax
            |     |        |-- CAUDOFOVEATA
            |     |        `--+-- TESTARIA
            |     |           `--+-- POLYPLACOPHORA 
            |     |              `-- CONCHIFERA
            |     `--+-- †Hyolitha
            |        `-- Sipuncula
            |--o "ANNELIDAMORPHA"
            |  |?- †Wiwaxia corrugata
            |  `--+?- †Canadia spinosa
            |           `-- Annelida 
            `--o LOPHOPHORATA