Taxonomy of Enteropneust Hemichordates

Taxonomic Key to the Enteropneusta

-modified from Cameron, 2002

1a) Stomochord with a vermiform process; pericardium and glomerulus with paired anterior
diverticula more or less developed (Spengeliidae)..............................................................................................................2
1b) Stomochord with no vermiform process; pericardium simple; ventral part of pharynx large,
and sometimes more or less separated from the branchial part............................................................................................5

2a) Liver-sacs and synapticles present; gill-slits almost equaling the pharynx in depth, so that
the ventral, non-pharyngeal part of the pharynx is reduced to a mere groove; nerve-roots
absent; pericardial diverticula long......................................................................................Schizocardium (Spengel, 1893)
2b) Liver-sacs absent; ventral part of pharynx well developed; pericardial diverticula short...............................................3

3a) Synapticles and nerve-roots absent................................................................................................................................4
3b) Synapticles present; nerve-roots present or absent; genital region with dermal pits...................Spengelia (Willey, 1898)

4a) Peribuccal spaces...................................................................................................................Willeyia (Punnett, 1903)
4b) Without peribuccal spaces................................................................................................Glandiceps (Spengel, 1893)

5a) Liver-sacs, synapticles and nerve-roots present (Ptychoderidae)..................................................................................6
5b) Liver-sacs, synapticles and nerve-roots absent (Harrimaniidae)...................................................................................8

6a) Genital wings well developed...............................................................................................................................…...7
6b) Genital wings hardly developed...................................................................................Glossobalanus (Spengel, 1893)

7a) Atrium opening by long slits.........................................................................................Ptychodera (Eschscholtz, 1825)
7b) Atrium opening by small pores...............................................................................Balanoglossus (Delle Chiaje, 1829)

8a) With many atria...........................................................................................................................................................9
8b) Without atria..................................................................................................Protoglossus (Caullery & Mesnil, 1904)

9a) Proboscis long; one proboscis pore..........................................................................................................................10
9b) Proboscis short.........................................................................................................................................................11

10a) burrowing.........................................................................................................Saccoglossus (Schimkewitsch, 1892)
10b) non burrowing................................................................................Saxipendium (Woodwick & Sensenbaugh, 1985)

11a) one proboscis pore; viviparous.......................................................................................Xenopleura (Gilchrist, 1925)
11b) usually two proboscis-pores...................................................................................................................................12

12a) Two pairs of genital wings..........................................................................................Stereobalanus (Spengel, 1901)
12b) No genital wings................................................................................................................Harrimania (Ritter, 1900)

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