DOI: 10.5061/dryad.fttdz08rt
title: Data from: Trophic partitioning and feeding capacity in Permian bryozoan faunas of Gondwana

description: Bryozoans are epibenthic suspension-feeders and use their ciliated
 tentacles to generate feeding currents. Modern bryozoan mouth size limits
 the size of the particles that can be ingested, and lophophore diameter is
 linked to water pumping rates. In fossil bryozoans these soft parts are
 absent, however, mouth and lophophore dimensions can be inferred from
 preserved skeletons. Gondwanan Permian palaeostomate bryozoans show
 distinct order-level trophic partitioning across warm to cold-water
 faunas. In diverse warm-water faunas of southern Thailand fenestrate
 bryozoans consume the smallest food particles, cryptostomes and
 trepostomes consume mid-size particles, and cystoporates consume the
 largest, and widest range, of particles. In contrast, in low diversity
 cold-water faunas of eastern Australia, where cystoporates and
 cryptostomes are uncommon, fenestrate bryozoans again consume the smallest
 food particles, however the abundant trepostomes have much larger mouths
 than their warm-water counterparts and consume the largest food particles.
 This plasticity in mouth size, especially in the trepostomes, suggests
 that mouth size is not controlled by systematics and that sessile benthic
 organisms are trophically structured to utilise different sized food
 particles from a suspended food source. Gondwanan Permian palaeostomates
 have much larger mouth and lophophore sizes than modern stenolaemates
 (cyclostomes) and are more comparable to gymnolaemate (cheilostome)
 bryozoans. This suggests that palaeostomates were able to access and
 consume the same range of food resources as modern bryozoans, and feed at
 similar rates, prior to the marine environmental changes at the close of
 the Palaeozoic, and that modern cyclostome stenolaemates are probably
 limited by the more successful cheilostomes.
description: PERMIAN DATA<br> Zooecial aperture dimension and apertural
 spacing data for Permian bryozoans were gathered from measurements
 provided in systematic descriptions of eastern Australia (Crockford
 1941a-b, 1943, 1945; Wass 1968; Reid 2003; Morozova 2004), Western
 Australia (Crockford 1944a-c, 1957; Ross 1963) and the Rat Buri Limestone
 of southern Thailand (Sakagami 1966, 1968a-c, 1970, 1971, 1973, 1975,
 1999; Reid 2001). The data for apertural size and closest spacing (centre
 to centre) were used in the form of averages, either directly as reported
 by the source, or calculated from maximum and minimum if only the range
 data were available. Where spacing data was not available in measurements,
 they were either taken from figured material, or calculated from quoted
 number of apertures in a given distance, or are left missing. Expected
 polypide mouth size and lophophore diameter (in millimetres) was
 calculated from mean skeletal aperture size using the regression formula
 of Tamberg & Smith (2020) derived from modern stenolaemate
 bryozoans. MD = 0.22 x [(AW+AL)/2] + 0.011mm<br>
 where MD is mouth diameter, AW aperture width and AL aperture
 length. LD = 1.9 x [(AW+AL)/2] + 0.1639mm<br>
 where LD is lophophore diameter. The equation of Snyder
 (1991) was also to calculate lophophore diameter as it utilises an
 alternative predictor.<br> LD = 1.5 x AS<br> where AS is
 closest apertural spacing. MODERN DATA<br> Mouth
 and lophophore diameter measurements of living cheilostome and cyclostome
 bryozoans were gathered from published literature (Borg 1944; Rogick 1949;
 Ryland 1967, 1975, 1977; Winston 1977, 1978, 1979; Best & Thorpe
 1986; Pouyet & Herrera-Anduaga 1986; Ryland & Hayward
 1991; Riisgård & Manríquez, 1997; Nielsen & Riisgård 1998;
 Gordon & Taylor 2001; Shunatova & Ostrovsky 2001; Ramalho
 et al. 2009; Ryland et al. 2009; Tamberg & Smith 2020) and new
 measurements collected by YT following techniques in Tamberg and Smith
 (2020). Lophophore diameter may be listed as tentacle crown diameter in
 publications on modern bryozoans. All measurements are
 in millimetres.
description: Refer to ReidTamberg2021bryozoaReadMe.txt.