TABLE 1. Occurrence of diatom fossils in TTM-1. “+” indicates the taxon that occurs as small fragment or that found during the observation after count of one hundred diatom valves.



Cocconeis spp. +
Coscinodiscus marginatus Ehrenberg 1
Delphineis surirella (Ehrenberg) G. W. Andrews +
D. simonsenii Yanagisawa et Akiba +
Neodenticula kamtschatica (Zabelina) Akiba et Yanagisawa 8
Nitzschia grunnowi Hasle +
N. rolandii Schrader emend. Koizumi 48
Paralia sulcata (Ehrenberg) Cleve 1
Rhizosolenia styliformis Brightwell 2
Thalassionema nitzschioides (Grunow) H. et M. Peragallo 26
Thalassiosira antiqua (Grunow) Cleve-Euler +
T. jacksonii Koizumi et Barron in Koizumi 2
T. marujamica Sheshukova-Poretzkaya 2
T. nidulus (Tempère et Brun) Jousé 1
T. temperei (Brun) Akiba et Yanagisawa 1
T. spp. 8
Total 100



TABLE 2. Measurements in mm of TTM-1: periotic and tympanic bulla. Measurements are rounded to the nearest 0.5 mm.

maximum anteroposterior length from anterior apex of anterior process to apex of posterior process 47.5
maximum anteroposterior length parallel to dorsal margin 48.0
maximum dorsoventral depth anterior process perpendicular to axis of periotic 17.5
length of anterior process from anterior apex to level of posterior of mallear fossa 17.0
length of anterior process from anterior apex of anterior process to level of anterior of pars cochlearis in notch immediately lateral to fine ridge 11.0
length facet on posterior process point to point 20.5
ventral opening of facial canal anteroposterior diameter  
maximum width of anterior process at base 14.0
approximate anteroposterior length of pars cochlearis 26.0
approximate transverse width of pars cochlearis from internal edge to fenestra ovalis 16.5+
transverse width of periotic, internal face of pars cochlearis to apex of lateral tuberosity 30.5+
length of posterior process of periotic 20.5
length of posterior process parallel to posterior profile/ steeply acute to long axis of body 20.5
Tympanic bulla  
standard length anterior apex to apex of outer posterior prominence 40.0+
length anterior apex to apex of inner posterior prominence 38.0+
dorsoventral depth of involucrum immediately in front of posterior pedicle 14.5



TABLE 3. Measurements in mm of TTM-1: teeth. Teeth numbers follow figure 7. Measurements are rounded to the nearest 0.5 mm. The asterisk (*) means squashed.

Total length 26.8
Crown length 10.8
Mediolateral diameter 5.1*
Anteroposterior diameter 10.1
B, I  
Total length 25.2+
Crown length 12.0
Mediolateral diameter 4.8*
Anteroposterior diameter 8.5
Total length 23.3+
Crown length 12.7
Mediolateral diameter 4.1*
Anteroposterior diameter 10.9
Total length 23.4+
Crown length 8.5+
Mediolateral diameter 5.1+
Anteroposterior diameter 8.0
Total length 20.5+
Crown length 9.0
Mediolateral diameter 7.0
Anteroposterior diameter 5.0
Total length 22.2+
Crown length 8.9
Mediolateral diameter 5.6
Anteroposterior diameter 7.9
Total length 18.8+
Crown length 11.0
Mediolateral diameter 4.7*
Anteroposterior diameter 7.3
Total length 23.7+
Crown length 9.6
Mediolateral diameter 5.0
Anteroposterior diameter 6.9
Total length 19.6
Crown length 12.0
Mediolateral diameter 4.1*
Anteroposterior diameter 8.0
Total length 12.6+
Crown length 7.9
Mediolateral diameter 4.6*
Anteroposterior diameter 7.9
Total length 19.7+
Crown length 9.7
Mediolateral diameter 5.2*
Anteroposterior diameter 7.2
Total length 22.4+
Crown length 8.4
Mediolateral diameter 6.6
Anteroposterior diameter 5.3
Total length 21.8+
Crown length 8.5
Mediolateral diameter 5.4
Anteroposterior diameter 6.5
Total length 15.4+
Crown length 8.7
Mediolateral diameter 5.9
Anteroposterior diameter 6.0+
Total length 13.6+
Crown length 13.6+
Mediolateral diameter 6.0+
Anteroposterior diameter 4.3+
Total length 19.0+
Crown length 8.1
Mediolateral diameter 6.0
Anteroposterior diameter 5.6