Table 2 Comparative data on the myoanatomy of Kinorhyncha from this study and available primary literature (references included)

Data source

TEM

TEM

LM

CLSM

CLSM

TEM

TEM

TEM

TEM, CLSM

Mouth cone

-

3 circular muscles

-

18 longitudinal, 2 circular muscles

16 longitudinal, 8 short basal and 2 circular muscles

18 longitudinal muscles

2 circular cell basal to oos, 7 circular muscle cells basal to ios

-

1 circular muscle cell basal to oos, 7 circular muscle cells basal to ios

Introvert

16 outer retractors 12 inner retractors

10 retractors reaching S.6

-

10 retractors reaching S.6, Introvert circular muscle

16 outer retractors reaching S.8

-

10 head retractors

-

10 head retractors

Neck

-

-

1- 5 circular muscles

1 circular muscle

2 circular muscles: inner outer

-

-

-

-

Trunk

-

-

Longitudinal: dorsal, ventral, and additional continuous fibers, Diagonal: 8 pairs Dorsoventral: S.3-11

Longitudinal: Ventromedial + Dorsolateral and additional continuous fibers, Diagonal: 8 pairs Dorsoventral: S.3-11

Longitudinal: Ventrolateral + Dorsolateral Diagonal: 9 pairs Dorsoventral: S.1-11

-

-

-

-

Spines

-

-

-

3 pairs LTS + 1 pair TE muscles 1pair penile spines muscles

Midterminal spine muscles triangle- shaped

-

-

-

-

Pharynx

Circular lumen

-

-

Circular lumen, 10 radial + 10 circular fibers

Circular lumen, 14–15 circular fibers alternate with inhomogeneous structures, pre- and postpharyngeal sphincters 10 protractors, Pharynx sheath present

Circular lumen, 15 radial +15 circular fibers,2 prepharyngeal 1postpharyngeal sphincters

Triradiate lumen

Triradiate lumen

Triradiate lumen

13 radial + 14 circular muscle cell

Circular and radial muscular fibers

13 radial + 14 circular muscle cell

1postpharyngeal sphincter

1postpharyngeal sphincter

1postpharyngeal sphincter

Midgut

12-16 longitudinal muscles

-

-

Muscular grid: Inner longitudinal (16) + outer circular (+16)

Muscular Grid: Inner longitudinal + outer circular

Muscular Grid: Inner longitudinal + outer circular

Muscular Grid: inner longitudinal + outer circular

-

Muscular Grid: inner longitudinal + outer circular

Hindgut

-

-

-

1-2 pairs short dilator muscles

1 dilator muscle

6 dilators: 2 caudal + 2 dorsal 1 frontal 1 circular

4 dilators: 2 caudal + 2dorsal; 2dorsal + 1 ventral transversal muscle cell

-

4 dilators: 2 caudal + 2dorsal; 2dorsal + 1 ventral transversal muscle cell

Reference

[1]

[33]

[41, 42]

This study

[26]

[30]

[30]

[38]

[5, 27, 30]