Phoronis pallida (Horseshoe worm):  

Predictions & Data for this entry

Model:  std  

MRE = 0.052
SMSE = 0.069

Zero-variate data
ab 6 5.987 (0.00223)dage at birthMeye2014
am3.65e+04 3.65e+04 (6.032e-05)dlife spanEmig2003
Lb0.005 0.004756 (0.04873)cmtotal length at birthSant2004
Lp 7 6.915 (0.01218)cmtotal length at pubertyguess
Li 14 14.6 (0.04272)cmultimate total lengthEmig1979
Wwi0.11 0.11 (0.0001929)gultimate wet weightEmig1979
Ri0.1918 0.1993 (0.03908)#/dmaximum reprod rateMeye2014
Uni-variate data
DatasetFigure(RE)Independent variableDependent variableReference
tL see Fig. 1 (0.1764)time since birthlengthSant2004
tLt see Fig. 1 (0.143)time since birthlengthSant2004
Pseudo-data at Tref
DataGeneralised animalPhoronis pallidaUnitDescription
v 0.02 0.001cm/denergy conductance
kap 0.8 1-allocation fraction to soma
kap_R 0.95 0.475-reproduction efficiency
p_M 18 0.4864J/^3vol-spec som maint
k_J 0.002 7.961e-051/dmaturity maint rate coefficient
kap_G 0.8 0.7998-growth efficiency
k 0.3 0.2997-maintenance ratio


  • Occurs at depths between 0 and 10 (till 100) m; Hermaphroditic. Giant nerve cells (ref: Emig1979)
  • Asexual reproduction is by transverse fission after sufficient gonadic material had been formed. The actinotroch larve swims for about 20 days, settles on the seabed and undergoes a catastrophic metamorphosis in 30 minutes (ref: Wiki)


  • The analysis assumes that pre- and post-metamorphic stages have the same parameters; this is probably incorrect and model abj probably applies
  • The assumed life span is probably much too long and the measured reproduction rate much too small
  • In view of low somatic maintenance, pseudodata k_J = 0.002 1/d is replaced by pseudodata k = 0.3


  • [Wiki]
  • [Emig1979] C. C. Emig. British and other Phoronids, volume 13. Acad. Press, London, 1979.
  • [Emig2003] C. C. Emig. Phylum Phoronida. In B. Grzimek, editor, Protostomes. Grzimeks Animal Life Encyclopedia, pages 491--497. Gale, Detroit, 2003.
  • [Kooy2010] S.A.L.M. Kooijman. Dynamic Energy Budget theory for metabolic organisation. Cambridge Univ. Press, Cambridge, 2010.
  • [Meye2014] K. Meyer. Bibtex files with references for this entry

    Bas Kooijman, 2014/07/29 (last modified by Bas Kooijman 2017/11/11)

    accepted: 2017/11/11

    refer to this entry as: AmP Phoronis pallida version 2017/11/11