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Table 1 Data available prior to this study on the musculature of Loricifera

From: A complete three-dimensional reconstruction of the myoanatomy of Loricifera: comparative morphology of an adult and a Higgins larva stage

Species LM/TEM Mouth cone muscles Introvert muscles Abdomen muscles Pharyngeal bulb  
   Longitudinal Radial Longitudinal Circular Others Longitudinal Circular   Reference
(Adults)           
Nanaloricus mysticus TEM 8 (inside the ridges) 16 (attached to the furcal base) 5 inner and 15–24 outer 2-3 (surrounding the brain) 6 buccal tube retractors; spinoscalid muscles; 10 rings (scalid rows) (nd) (nd) a) myoepithelial, radial musculature [12, 20, 21]
Armorloricus elegans* TEM, LM (np) (np) 6 inner and at least 15 outer; 1 dorsal pair spans through the whole body (widely separated) 1 (surrounding the brain) spinoscalid muscles 1 dorsal pair (same fiber that runs in the introvert) several diagonal and dorso-ventral muscles myoepithelial, radial musculature [2, 12, 25]
Pliciloricus enigmaticus TEM 8 (inside the ridges) 16 (attached to the furcal base) 5 inner and 15–24 outer 2-3 (surrounding the brain) spinoscalid muscles; scalid ring musclesb) 20-22 11 (ring-like) myoepithelial, radial musculature [20]
Pliciloricus pedicularis LM 8 (run through the brain) 1 pair large; neighbor retractors present (smaller) 1 (ring-like) spinoscalid large diagonal muscles several (located anteriorly) several transverse muscles; 1 (ring-like, posterior) 3 transversal layers of radial muscles [10]
Pliciloricus diva LM 8 (run through the brain) 1 pair large; neighbor retractors present (smaller) c) spinoscalid diagonal muscles; scalid ring muscles several (located anteriorly) 3 layers of transverse muscles; (nd) [11]
Rugiloricus doliolius LM 8 (run through the brain) 1 dorsal pair (large) c) spinoscalid muscles; scalid ring muscles several bundles many bundles (ring muscles) (nd) [16, 26]
Rugiloricus renaudae LM present present present spinoscalid muscles several strings narrow bundles (transverse) (nd) [13]
(Higgins larva)           
Pliciloricus pedicularis LM several several (transverse) muscles arranged in five layers of 3 radial muscles [10]
Pliciloricus diva LM muscles arranged in five layers of 3 radial muscles [11]
Rugiloricus doliolius LM 6 short 8 c) spinoscalid muscles 8 (ventral pair strongest); toe base muscles 7 ring muscles (nd) [16, 26]
  1. *Description partially based on direct observations of images published in Kristensen [25] and Bang-Berthelsen et al. [12]; (−), not found; (nd), included in figures but not described; (np), images not provided; a)Though a neck circular muscle is described in Bang-Berthelsen et al. [12]; b)Fewer than in N. mysticus; c)Though transverse (or ring) muscles are described in the thoracic region.Myoanatomical features of adult and Higgins larva stage observed by light (LM) or transmission electron microscopy (TEM).