PMC

Anatomy of walking leg 10 and ultimate leg. a 3D volume rendering of walking leg 10 and musculature, microCT analysis. Note that muscles labeled in bold either exhibit differences to ultimate leg muscles (m40 and m41, compare b) or are absent in the ultimate leg (m37). b 3D volume rendering of ultimate leg and musculature, microCT analysis. Note that muscles labeled in bold exhibit differences to walking leg 10 (compare a). c Detail of ultimate leg tibia showing ventrolaterad displacement of the claw tendon (td1), nerve N4, and muscle m48 by the tissue of the telopodal glands (teg). d Ultimate leg articulation of tarsus 1 and 2 with N4 branching in the proximal part of tarsus 2. Pores of telopodal glands are detectable in this visualization. e Tibio-tarsal articulation of the ultimate leg showing the branching of N4 in the proximal tarsus 1. Tarsus 1 houses a presumptive second tendon (td2?) supplied by a single muscle head from m48. f Right ultimate leg coxa from ventral. Note that the levator and depressor muscles m40 and m41 are substantially enlarged (compare a). Abbreviations: cl claw, cx coxa, fe femur, li connective tissue ligament, m muscle. N nerve, pfe prefemur, ta tarsus, td1 claw tendon, td tendon, teg telopodal gland tissue, ti tibia, tr trochanter

The geophilomorph centipede Haplophilus subterraneus. a Male specimen with focus on head and posterior trunk. Note the morphological disparity of locomotory and ultimate legs. b Female posterior trunk with ultimate legs, view from ventral (locomotory legs partially omitted). c Male posterior trunk with ultimate legs, view from ventral (locomotory legs partially omitted). Abbreviations: an antennae, cxp coxal pores, ul ultimate legs

SEM analysis of the ultimate legs of female Haplophilus subterraneus. a Posterior trunk from ventral. Note the shape and insertion of ultimate legs in comparison to locomotory legs. b Stalked ducts of epidermal glands scattered on the tibia. Note also the trichoid sensillum in the lower center (st; with characteristic socket). c Ventromedial side of female ultimate leg. Abbreviations: ap anal pore, cx coxa, cxp coxal pores, fe femur, gp gonopods, ll locomotory leg, pfe prefemur, st sensillum trichodeum, ste sternite, ta1 tarsus 1, ta2 tarsus 2, ti tibia, ul ultimate leg

Biomechanical analysis indicates day 3 toroids can withstand greater deformation before failure and exhibit greater ultimate tensile strength than day 6 toroids. Treatment with Y-27632 significantly increased the displacement at failure of day 3 toroids as compared to day-matched control. Error bars indicate standard deviation. * indicates day 3 control ultimate tensile strength with respect to day 6 control and day 6 inhibitor-treated ultimate tensile strengths (two-way ANOVA, Bonferroni post-test, p<0.05); # indicates day 3 inhibitor-treated displacement at failure with respect to day 3 control and day 6 control displacements at failure, and day 3 inhibitor-treated ultimate tensile strength with respect to day 6 control and day 6 inhibitor-treated ultimate tensile strengths (two-way ANOVA, Bonferroni post-test, p<0.05).