Diogenichthys sp.

Fig. 9 Fish otoliths from the Lower Pliocene Gutingkeng Formation, southern Taiwan. Scale bars=1 mm. Images are inner views unless otherwise indicated. a Diogenichthys sp., Site 5, sand layer, ASIZF 0100628. b–c Myctophum sp., Site 5, sand layer, ASIZF 0100629–630. d Notoscopelus resplendens (Richardson, 1845), Site 5, sand layer, ASIZF 0100631. e Lampanyctus alatus Goode & Bean,1896,Site 5, sand layer, ASIZF 0100632. f–h Coelorinchus sp., ASIZF 0100633–635, f–g Site 2, h Site 5, sand layer. 1, ventral view; 2, inner view

Fig. 19 Extant otoliths of Sparidae from Taiwan.Scale bars =1 mm. Images are inner views.a–b, Acanthopagrus chinshira Kume & Yoshino, 2008, a 24 Dec. 2020, 232.86 mm SL, CHLOL 1937, b 28 Aug. 2019, 182.27 mm SL, CHLOL 621. c–d Acanthopagrus latus (Houttuyn, 1782), c, 31 Oct. 2019, 226.97 mm SL, CHLOL 674, d 31 Oct. 2019,233.84 mm SL,CHLOL 688. e–f Acanthopagrus pacificus Iwatsuki, Kume & Yoshino 2010, e 28 Aug. 2019, 300.32 mm SL, CHLOL 625, f 10 Feb. 2020, 230.00 mm SL, CHLOL 737. g–h Acanthopagrus schlegelii (Bleeker, 1854), g 28 Aug. 2019,156.12 mm SL, CHLOL 622, h 19 Jan. 2020, 173.88 mm SL, CHLOL 718. i–j Acanthopagrus sivicolus Akazaki, 1962, i 31 Oct. 2019,223.51 mm SL,CHLOL 683, j 31 Oct. 2019,217.26 mm SL,CHLOL 684. k Acanthopagrus taiwanensis Iwatsuki & Carpenter, 2006, 24 Dec. 2020, 223.56 mm SL, CHLOL 1938. l–n Rhabdosargus sarba (Forsskål, 1775), l 31 Oct. 2019, 203.79 mm SL,CHLOL 697, m 18 Dec. 2020, 144.89 mm SL, CHLOL 1643, n 21 Aug. 2019, 172.10 mm SL, CHLOL 578

Fig. 20 Extant otoliths of Sparidae from Taiwan.Scale bars =1 mm. Images are inner views.a–d Dentex hypselosomus Bleeker,1854,a 3 Sep. 2021, 133.64 mm SL, CHLOL 12954,b 25 Jul.2020,211.22 mm SL,CHLOL 955, c, 15 Aug. 2020, 260.48 mm SL,CHLOL 1190,d 3 Sep. 2021, 89.04 mm SL, CHLOL 12951.e–h Argyrops bleekeri Oshima, 1927, e 4 Apr. 2022, 43.44 mm SL,CHLOL 17282, f 16 Apr. 2022, 54.79 mm SL,CHLOL 17425, g 17 Jun. 2022, 320.41 mm SL,CHLOL 18574,h 3 Jun. 2022, 96.95 mm SL,CHLOL 18528. i–l Evynnis cardinalis (Lacepède, 1802), i 28 Aug. 2019,130.88 mm SL, CHLOL 643, j 3 Sep. 2021, 100.93 mm SL, CHLOL 12236,k, 3 Sep. 2021, 59.38 mm SL,CHLOL 11976, l 31 Oct.2019,162.74 mm SL,CHLOL 695. m–p Evynnis tumifrons (Temminck & Schlegel,1843), m 25 Jul. 2020, 192.32 mm SL, CHLOL 956, n 3 Sep. 2021, 125.10 mm SL, CHLOL 11388,o 26 Oct. 2021, 84.32 mm SL, CHLOL 10206, p 15 Aug. 2020, 242.99 mm SL, CHLOL 1159. q–s Pagrus major (Temminck & Schlegel, 1843), q 24 Apr. 2021, 260.38 mm SL, CHLOL 5451, r 17 Aug. 2022, 108.88 mm SL, CHLOL 19786, s 24 Apr. 2021, 183.25 mm SL,CHLOL 5443

Fig. 21 Differences in density of otoliths (a–b) and species richness (c–d) for the sampled sites.Box plots with lower (25th percentile),median, and upper (75th percentile) boundaries, and outliers (solid circle) outside of 10th and 90th percentiles are presented. Note change of scale for samples from the sand layers in Kaohsiung (c–d)

Fig. 1 Maps showing the sampling sites.a Overview of geological map of Taiwan (modified after Chen, 2016). b Detailed geological map of study area (map extracted from National Geological Data Warehouse, Central Geological Survey, Ministry of Economic Affairs,Taiwan). c–d Detail maps of the sampling sites in Chochen,Tainan (c) and Tianliao,Kaohsiung (d)

Fig. 2 Stratigraphic correlation of the southern part of the Western Foothills in Taiwan (modified after Chen, 2016). The studied formation, the Gutingkeng Formation, is indicated in yellow