Table 1 Comparative larval myoanatomy of the rhynchonelliform brachiopods Argyrotheca cordata, Terebratalia transversa, and A. cistellula

apical longitudinal muscles

+

+

+

apical lobe

alm

apical transversal muscle

+

+

+ (apical muscle ring)

apical lobe

atm

central mantle muscles

+

+

+ (dorsal mantle muscles)

mantle lobe

empty arrowheads

circular mantle muscle

+

+

+ (posterior muscle ring)

mantle lobe

arrows

lateral mantle muscle

-

-

+

mantle lobe

lmm

longitudinal muscles

+

+

-

mantle and pedicle lobe

lm

pedicle muscles

+

+

+

pedicle lobe

pm

serial mantle muscles

+

+

+

mantle lobe

double arrowsheads

setae muscles

+

+

-

mantle lobe

sm

setae pouch musculature

+

+

-

mantle lobe

arrowheads

U-shaped muscle

+

+

+ (ventral mantle muscle)

mantle lobe

empty arrows