9780521861724htl 1..2

meiofauna–macrofauna size spectrum, but these have confirmed the bimodal
species size distribution, with many meiofaunal and many macrofaunal
species, but few of intermediate size (Warwicket al., 1986 ;Warwick&Joint,
1987 ;Kendall,Warwick&Somerfield,1997 ). An intuitive explanation for this
follows Schwinghamer’s (1981 ) explanation for the ataxonomic benthic biomass
spectrum concerning the constraint on body size of sediment granulometry.

10 –1 100 101 102 103 104

Length (mm)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

Number of species

Figure 11.1Numbers of species in regional species pools of guilds of marine animals
divided into size categories on a1:28 geometric scale. 1 – Tardigrades, Britain (Morgan &
King, 1976 ); 2 – Selective deposit feeding (bactivorous) nematodes, Chile (Wieser, 1959 );
3 – Non-selective deposit feeding nematodes, Chile (Wieser, 1959 ); 4 – Epistrate (diatom)
feeding nematodes, Chile (Wieser, 1959 ); 5 – Carnivorous/omnivorous nematodes, Chile
(Wieser, 1959 ); 6 – Harpacticoid copepods, Norway (Sars, 1911 ); 7 – Calanoid copepods,
Norway (Sars, 1903 ); 8 – Ostracods, Norway (Sars, 1928 ); 9 – Gammarid amphipods, Britain
(Lincoln, 1979 ); 10 – Cumaceans, Britain (Jones, 1976 ); 11 – Mysids, Britain (Tattersall &
Tattersall, 1951 ); 12 – Shrimps and prawns, Britain (Smaldon, 1979 ); 13 – Filter-feeding
bivalves, Britain (Tebble, 1966 ); 14 – Ophiuroids, Britain (Mortensen, 1927 ); 15 – Regular
echinoids, Britain (Mortensen, 1927 ); 16 – Irregular echinoids, Britain (Mortensen, 1927 );
17 – Flatfish, NW Europe (Wheeler, 1969 ); 18 – Gadoids, NW Europe (Wheeler, 1969 );
19 – toothed whales, Europe (Van den Brink, 1967 ).

BODY SIZE AND DIVERSITY IN MARINE SYSTEMS 213