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Figure Legends

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Figure 1. Morphological features of nasal cavity of green sea turtles.

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(A) Left lateral view of the head. Boxed area indicates the nasal area and corresponds to

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panels (B-D). (B) Outer nasal cartilages after removing bones encircling nasal area. (C)

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Internal structure of nasal cavity after removing left half. (D) Alcian blue (pH 2.5) and

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alizarin red stained image corresponding to panel (C). Connective tissue containing

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cartilages (arrowheads) positive for Alcian blue distinctly separates anterodorsal (1) and

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anteroventral (2) diverticula, posteroventral excavation (3) and posterodorsal

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diverticulum (4). *Nostrils.

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Figure 2. Internal structures of nasal cavity of green sea turtles.

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(A) Three-dimensional image of head reconstructed from computed tomographic (CT)

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images. Air in nasal cavity is extracted in yellow to visualize internal structure of nasal

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cavity. Boxed area corresponds to panels (B-E). (B) CT image of nasal cavity shows four

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distinct structures. (C-E) Left lateral (C), frontal (D) and dorsal (E) views of three-

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dimension reconstructed images of the nasal cavity. Anterodorsal (1) and anteroventral

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(2) diverticula, posteroventral excavation (3) and posterodorsal diverticulum (4).

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*Nostrils.

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Figure 3. Simulation of water inflow into nasal cavity.

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Model of internal structure of nasal cavity (upper). Silicon molding submerged in water

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at horizontally (0°), upwards (about 40°) and downwards (90°) (middle), and schemes of

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water inflow at each location (lower). Upper side is water surface. Minimal amount of

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water enters posterodorsal diverticulum (arrows). Water fills anterodorsal diverticulum

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(arrowheads) in upward and downward positions. Blue and white areas in nasal cavity

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indicate water and air, respectively. *Nostrils.

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Figure 4. Projection of nerve bundles derived from nasal cavity.

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(A) Dorsal view of nasal cavity and anterior brain region after removing skull. Left side

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is anterior. Left and right olfactory nerve tracts (arrow) originate from nasal cavity (NC)

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and reach olfactory bulbs (OB) located at front of cortex (Cor). *Orbit. (B) Dorsal view

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of right olfactory nerve tract. Left olfactory nerve tract is removed. Dorsolateral part (dl)

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is derived from posterodorsal diverticulum (4), and ventromedial part (vm) is derived

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from other regions of nasal cavity. (C and D) Left lateral view (upper) and trace (lower)

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of nerve distribution in right nasal cavity before (C) and after (D) removing nasal septum.

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Several thin nerve bundles derived from anterodorsal (1) and anteroventral (2) diverticula

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form ventromedial part (vm) of olfactory nerve tract (blue lines). Single thin bundle of

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nerves (arrows) is derived from posteroventral excavation (3) and runs in most medial

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region (red lines). Dorsolateral part (dl) of olfactory nerve tract is derived from

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posterodorsal diverticulum (green lines). (E) Scheme of left lateral view of nerve

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distribution in right nasal cavity according to panels (C and D).

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Figure 5. Distribution of epithelia in nasal cavity.

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Lateral view of nasal cavity region (top) and frontal section of nasal cavity based on

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histological findings (bottom). Straight lines with alphabetical letters in top panel indicate

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positions corresponding to images with same letters. Blue, red and green lines indicate

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separate types of sensory epithelia. Black line indicates non-sensory epithelium.

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Anterodorsal (1) and anteroventral (2) diverticula, posteroventral excavation (3) and

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posterodorsal diverticulum (4).

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Figure 6. Histological features of sensory epithelium covering anterodorsal and

anteroventral diverticula.

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(A) Whole epithelium stained with hematoxylin-eosin. Arrowheads indicate basal cells.

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ZON, zone of oval nuclei; ZRN, zone of round nuclei. (B) High magnification of ZRN.

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Arrows and arrowheads indicate nuclei of supporting-like cells and bipolar receptor cells,

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respectively. (C) Anti-HuC/HuD immunoreaction in ZRN. Arrows and arrowheads

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indicate negative and positive cells, respectively. Bar = 30 μm.

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Figure 7. Histological features of sensory epithelium covering posteroventral excavation.

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(A) Whole epithelium stained with hematoxylin-eosin. Arrowheads indicate basal cells.

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ZON, zone of oval nuclei; ZRN, zone of round nuclei. (B) High magnification of ZRN.

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Arrows and arrowheads indicate nuclei of supporting-like cells and bipolar receptor cells,

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respectively. (C) Anti-HuC/HuD immunoreaction in ZRN. Arrows and arrowheads

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indicate negative and positive cells, respectively. Bar = 30 μm.

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Figure 8. Histological features of sensory epithelium covering posterodorsal

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diverticulum.

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(A) Whole epithelium with olfactory gland (asterisk) in lamina propria, stained with

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hematoxylin-eosin. Arrowheads indicate basal cells. ZON, zone of oval nuclei; ZRN,

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zone of round nuclei. (B) High magnification of ZRN. Arrows indicate nuclei of bipolar

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receptor cells. (C) Anti-HuC/HuD immunoreaction in ZRN. Arrowheads indicate positive

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cells. Bar = 30 μm.

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Supplementary Table 1.

TAAR, V1R and V2R genes in green sea turtle based on the genomic information.

Receptor family

Genbank accession

TAAR*

XM_007062262.2

XM_007062261.1

XM_007062260.2

XM_007062259.2

XM_007062257.1

XM_007062256.1

XM_007062255.1

XM_007062254.1

XM_007062253.2

XM_007062247.2

XM_007062246.2

XM_027824652.1

XR_443470.2

V1R†

XM_007059608.1

XM_007067150.1

V2R†

(EMP28964.1; protein database)‡

* The locus of TAAR on chromosome are conserved among reptiles, and TAAR genes

are located near vanin 1 gene to form a gene cluster. We counted the number of TAAR

genes on contig: NW_006637070.1.

TBLASTN search (Camacho et al. 2009) were performed on refseq RNA sequences to

retrieve green sea turtle V1R and V2R genes. Query sequences were total 244 and 215

protein sequences of V1R and V2R, respectively, in four vertebrates; zebrafish (Danio

rerio), western clawed frog (Xenopus tropicalis), mouse (Mus musculus) and Chinese

soft-shell turtle (Pelodiscus sinensis).

Blast results did not show any V2R in green sea turtle, but protein database suggests one

V2R and genome information indicates one pseudo gene (Gene ID: 102943443) in green

sea turtles.

Camacho C, Coulouris G, Avagyan V, Ma N, Papadopoulos J, Bealer K, Madden TL.

2009. BLAST plus: architecture and applications. BMC Bioinformatics. 10:1.

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