Craniofacial features of stages 19–21 <i>S</i>. <i>crassicaudata</i>.

<p>Haematoxylin/eosin staining through rostral (left) and caudal (right) regions of the head of <i>S</i>. <i>crassicaudata</i> at stages 19 (A), 20 (B), and 21 (C) in the coronal plane (postnatal days 4–7, 8–11, and 12–15, respectively). Insets of the developing eye at corresponding ages (D-F, respectively). ac, anterior commissure; BG, basal ganglia; Cg, cingulate cortex; Cla, claustrum; Co, cornea; CP, cortical plate; ec, external capsule; En, endopiriform nucleus; Ey, eye; Et, ethmoid bone; F, follicle; Ga, ganglion layer; GE, ganglionic eminence; Hp, hippocampus; ic, internal capsule; IG, indusium griseum; L, lens; LE, lens epithelium; LF, lens fibres; Li, eyelid; lot, lateral olfactory tract; LV, lateral ventricle; LVe, lens vesicle; Mb, mandibulary process; Mo, mouth; Mx, maxillary process; MZ, marginal zone; NC, nasal cavity; Nb, neuroblastic layer; OE, olfactory neuroepithelium; ON, optic nerve; Orb, orbital bone; OS, optic stalk; OT, olfactory tubercle; Pi, pigment epithelium; Pir, piriform cortex; PoA, preoptic area; Pp, preplate; PSp; presphenoid bone; Re, retinal layer; Se, septum; Sp, subplate; St, striatum; SVZ, subventricular zone; T, tongue; VZ, ventricular zone. Scale bars: 500 μm (A-C), 100 μm (E-F).</p

External body features of newborn <i>S. crassicaudata</i>.

<p>Microphotograph of a stage 18 newborn dunnart as seen from the right and from the front. Note the prominent orofacial features, including fused mandible (Mb), and wide nostrils (N). The eyes (Ey) are small and lightly pigmented. Forelimbs are more advanced than hindlimbs, with digits serrated as compared to completely fused. Scale bar: 1mm.</p

Craniofacial features of newborn <i>S</i>. <i>crassicaudata</i>.

<p>(A) Schematic of a stage 18 dunnart head (postnatal day 0–3) indicating the relative size and position of nostrils, mouth, tongue, eyes and brain, as well as the section planes shown in (B-D). (B-D) Haematoxylin/eosin staining of a rostral-caudal series through the planes depicted in panel A reveals orofacial, sensory and brain structures of newborn dunnarts, including a prominent tongue (T) that encloses the teat inside the mouth (Mo) reaching the lateral margins of the palate (Pal). Large nasal cavities (NC) with fused palate (Pal) and nasal septum (NSe) can be seen, including condensation of mandibular (Mb) and maxillary (Mx) processes, eyes (Ey) fully covered by skin, and scattered vibrissal follicles (VF) in the snout. Telencephalic structures include the olfactory bulb (OB), with surrounding olfactory nerve layer (onl), preplate (Pp), ventricular zone (VZ) and ganglionic eminences (GE) as well as a large lateral ventricle (LV). E-F, inset of the regions highlighted in B-D depicting developing sensory structures. E, the vomeronasal organ (VO) includes a lumen (VLu), neuroepithelium (VE) and capsule (VC) at the base of NSe and Pal. F, a thick olfactory neuroepithelium (OE) is located at the roof of the NC, immediately below the presumptive cribiform plate (CrP). G, eye development has just undergone closure of the lens vesicle (LVe), the pigment epithelium (Pi) outlines a dark ring around cells of the retina (Re). Et, ethmoid bone; Orb, orbital bone; PoA, preoptic area; PSp; presphenoid bone. Scale bar: 500 μm.</p

Non-linear regression statistics for <i>S</i>. <i>crassicaudata</i> growth curves.

<p>Non-linear regression statistics for <i>S</i>. <i>crassicaudata</i> growth curves.</p

Morphometric measurements in postnatal <i>S</i>. <i>crassicaudata</i>.

<p>Morphometric measurements in postnatal <i>S</i>. <i>crassicaudata</i>.</p

Developmental growth curves of postnatal <i>S</i>. <i>crassicaudata</i>.

<p>Semilogarithmic relationships between the postnatal age (in days) and crown-rump length (A), head width (B), forelimb length (C), and hindlimb length (D). Mean ± standard error of the mean, as well as best-fit regression curves (red lines) and 95% confidence intervals (dotted lines) are indicated in each case. Non-linear functions whereby <i>y</i> indicates the corresponding measurements (in mm) and <i>x</i> the age in days, as well as <i>R</i>^<i>2</i> values are indicated. See Tables <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184450#pone.0184450.t001" target="_blank">1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184450#pone.0184450.t002" target="_blank">2</a> for additional information.</p

Developmental series of postnatal <i>S</i>. <i>crassicaudata</i>.

<p>A system of twenty-nine arbitrary stages from conception to weaning is included to match equivalent stages in human (Carnegie staging system) and mouse (Thieler staging system). Birth occurs at stage 18. Corresponding age of each stage is included as a range of postnatal days (P). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184450#pone.0184450.t003" target="_blank">Table 3</a> for further details. Scale bar: 5 mm.</p

Brain features of <i>S</i>. <i>crassicaudata</i> between stages 27 and adulthood.

<p>Developmental series of fixed dunnart brains showing a dorsal view of the whole brain (left column) and corresponding DAPI-stained coronal section (right column) through the approximate region indicated by dotted lines. The main brain regions are colour-coded, and stages and approximate postnatal (P) days are indicated. Arrowheads show the rhinal fissure (rf). ac, anterior commissure; BS, brainstem; CA, cornu ammonis hippocampi; Cb, cerebellum; Cd, caudate; Cg, cingulate cortex; Cla, claustrum; DG, dentate gyrus; ec, external capsule; En, endopiriform; f, fornix; hc, hippocampal commissure; ic, internal capsule; IC, inferior colliculus; Ins, insular cortex; IsoCx, isocortex; L1-6, isocortical layers 1–6; lot, lateral olfactory tract; MZ, marginal zone; OB, olfactory bulb; OT, olfactory tubercle; Pir, piriform cortex; Pir2, piriform cortex, layer 2; PoA, preoptic area; Pu, putamen; SC, superior colliculus; Se, septum; SP, subplate; SVZ, subventricular zone; VZ, ventricular zone. Scale bars: 2000 μm in whole brains, and 200 μm in coronal sections.</p