I don't see かわがめ in my refs. 革亀・おさがめ is an odd one but it's in a couple refs.

Google N-gram Corpus Counts
╭─ーーーー─┬───────┬───────╮
│ 長亀　　 │ 1,238 │ 26.2% │
│ 革亀　　 │     0 │  0.0% │ - rK (kanjipedia, koj)
│ おさがめ │    45 │  1.0% │
│ かわがめ │     0 │  0.0% │ - drop
│ オサガメ │ 3,351 │ 70.9% │ - move up
│ カワガメ │    93 │  2.0% │
╰─ーーーー─┴───────┴───────╯

@@ -8,0 +9 @@
+<ke_inf>&rK;</ke_inf>
@@ -10,7 +10,0 @@
-<r_ele>
-<reb>おさがめ</reb>
-</r_ele>
-<r_ele>
-<reb>かわがめ</reb>
-<re_restr>革亀</re_restr>
-</r_ele>
@@ -19,0 +14,3 @@
+</r_ele>
+<r_ele>
+<reb>おさがめ</reb>

Entry created