FIGURE 1. Paleogeographic map from the Early Jurassic indicating where Uncina lobsters have been found (Feldmann and Copeland, 1988; Karasawa, 2002; Schweigert et al., 2003; Martindale et al., 2017). The yellow star represents Ya Ha Tinda, Alberta, Canada, the red star represents the European sites bearing Uncina alpina and U. posidoniae, and the orange star represents the modern-day Japanese site bearing Uncina pacifica (Karasawa, 2002). Figure modified from Martindale et al. (2017).
FIGURE 2. Stratigraphic column of the East Tributary of Bighorn Creek section, Ya Ha Tinda Ranch, Alberta, Canada. Symbols denote the stratigraphic heights at which crustacean material was found as well as the elements and species (if applicable). Sepent. = Serpentinum, Falcif. = Falciferum, Eu = Europe, NA = North America. Lithostratigraphy and carbon isotope curve from Them et al. (2017) and fossil heights from Martindale et al. (2017). Some specimens are not reported from a particular horizon; instead, the collector Russell Hall (an ammonite biostratigrapher) noted the ammonite zone and so the age is assumed to be correct (dashed range). Specimens found in float from East Tributary can be assigned a minimum age; the river cuts up-section and so specimens not found in situ are interpreted to have originated from strata that are stratigraphically below the horizon in which they were found (dashed arrow).
FIGURE 3. Selected specimens of Uncina ollerenshawi; all whitened with ammonium chloride. A) Holotype specimen of U. ollerenshawi (GSC 80067). Specimen is a molt (Feldmann and Copeland, 1988) found at GSC locality 75402, above a small waterfall on Bighorn Creek, Fernie Formation, Pliensbachian age. B) Nearly complete molt specimen of U. ollerenshawi (TMP 2014.021.0052). Late Pliensbachian in age, collected from the Red Deer Member of the Fernie Formation at the East Tributary of Bighorn Creek locality at Ya Ha Tinda Ranch, Alberta, Canada. C) Claw of the first pereiopod of U. ollerenshawi (TMP 2015.051.0063). Ya Ha Tinda Ranch of Alberta, Canada, Fernie Formation, Red Deer Member, Exact age unknown, collected from the Red Deer Member of the Fernie Formation at the Scalp Creek locality at Ya Ha Tinda Ranch, Alberta, Canada. D) Sketch of TMP 2015.051.0063 to scale. E) Close up of the chelae from the holotype of U. ollerenshawi (GSC 80067). F) Close up of the tail from the holotype of U. ollerenshawi (GSC 80067), faint outlines of the uropods and telson annotated, arrow identifies the straight diaeresis on the exopod.
FIGURE 4. Selected specimens of Uncina pacifica (all whitened with ammonium chloride unless otherwise noted). All specimens are Toarcian in age and were collected from the Red Deer Member of the Fernie Formation at the East Tributary of Bighorn Creek locality at Ya Ha Tinda Ranch, Alberta, Canada. A) Near complete specimen of U. pacifica (TMP 2014.021.0002), imaged in polarized light. B) Full body specimen of U. pacifica (TMP 2017.015.00001), possible molt, otherwise poorly preserved. Specimen has both chelae of the first pereiopod preserved and demonstrates that U. pacifica is heterochelous. C) Isolated minor chela of the first pereiopod of U. pacifica (TMP 2017.015.0005). D) Isolated major chela of the first pereiopod of U. pacifica (TMP 2014.021.0003).
FIGURE 5. Morphological variation of the chelae of the first pereiopod in the four Uncina species. All sketches are based on real specimens but are shown at approximately the same size to facilitate comparison of morphologies between species (i.e., sketches were either enlarged or reduced proportionally). A) Uncina pacifica, minor claw, specimen TMP 2014.021.0003, B) Uncina ollerenshawi, specimen TMP 2015.051.0063. C) Uncina posidoniae, specimen from the Hauff collection, D) Uncina alpina, redrawn from Schweigert et al. (2003, pl. 10, fig. 4).
FIGURE 6. Box plots of morphometric measurements from Uncina species; the tops and bottoms of the colored boxes indicate the first and third quartile respectively and the solid black lines within represent medians. The whiskers outside of the boxes represent the lowest and highest datum (within 1.5 times the interquartile range), open circles outside of the whiskers indicate outliers; “n” refers to number of specimens (per species) with which that variable could be measured. A) Ratio of the propodus notch length to notch height in different species of Uncina. B) Ratio of the index length to index height in different species of Uncina. C) Total length of chelae in different species of Uncina. D) Ratio of manus length to index length in different species of Uncina. E) Ratio of the dactylus thickness to index height in different species of Uncina. F) Ratio of manus height at its minimum to manus height maximum for each uncinid species.
FIGURE 7. Known age ranges of the four Uncina species confirmed based on in situ fossil collections (note that the occurrence is not resolved below ammonite zones). Range through data are denoted with dashed lines (assumed). Age ranges for U. alpina (1 = Garassino and Teruzzi, 2001; 2 = Jenkyns et al., 1985) and U. posidoniae from Hauff and Hauff (1981), Schweigert et al. (2003); ages of U. pacifica from Karasawa (2002), Schweigert et al. (2003), Nakada and Matsuoka (2009), Martindale et al. (2017), and this work (including Hall’s collection notes at the Royal Tyrrell Museum of Palaeontology); and ages of Uncina ollerenshawi from Feldmann and Copeland (1988), Schweigert et al. (2003), Martindale et al. (2017), and this work. Amm. Zone = Ammonite Zone.
