Erenna

Pugh, P. R. & Haddock, S. H. D., 2016, A description of two new species of the genus Erenna (Siphonophora: Physonectae: Erennidae), with notes on recently collected specimens of other Erenna species, Zootaxa 4189 (3), pp. 401-446 : 442

Key to Erenna species based on their nectophores.

1 Long "horn" canals arising from lateral radial canals; thrust block without median indentation.. Erenna cornuta Pugh, 2001

- No "horn" canals. Thrust block with median indentation...................................................... 2

2 Mature nectophores with digitate processes on thrust block.................................................... 3

- Mature nectophores without digitate processes on thrust block................................................. 4

3 Upper lateral ridges divide close to ostium. Incomplete lateral ridges present............... Erenna richardi Bedot, 1904

- Upper lateral ridges undivided. No lateral ridges........................................... Erenna sirena sp. nov.

4 Upper lateral ridges divide close to ostium forming broad "m"-shaped branches. Thrust block consisting of one pair of lobes............................................................................... Erenna laciniata Pugh, 2001

- Upper lateral ridges undivided. Thrust block with two pairs of lobes........................ Erenna insidiator sp. nov.