This issue's installment of Alley Oop highlights the pteranodon. Statted in Hideouts & Hoodlums Supplement II: All-American, the pteranodon, at "only" 2+1 Hit Dice, is the dinosaur you're most likely to walk away from a fight with at lower levels.
Captain Easy continues to make it easy for me to stock H&H with giant animal mobster-types. Here we get giant lizards (statted in Book II: Mobsters & Trophies) and a 30' long shark. In the schema of ordinary/large/huge/giant that some animals get, the 6+1 HD shark in Book II would be a "large" shark, which would make this a "huge" shark at 12+2 HD (this is even corroborated on the next page, which calls it a "huge shark").
Note the combination of on land and underwater locations in the lost city, and that the best trophies seem to be hidden in the underwater locations.
Turtles have never been statted for H&H. These are 300 lb. turtles and, since a leatherback sea turtle can grow as heavy as 1 ton, these don't come close to being giant animals. At best, these would warrant an entry for ordinary turtles, weigh in at 2 Hit Dice, and perhaps with just a note that giant turtles are much, much bigger.
The giant stingray was statted in Book II: All-American.
Boots continues to toy with being an action-adventure strip. Check out this multi-level hideout, concealed in a hill, accessible through an ordinary-looking house on the top. On the back side of the hill is a machine gun nest/look-out point, and two concealed hangar bays. The bad guys were capable of launching a small air force of 11 planes into the air!
Here, Dan Dunn continues to enter superhero territory, as he takes on a mad scientist with a blimp, and an electric raygun (all three -- scientists, blimps, and electric rayguns -- were statted in Book II).
(Scans courtesy of the Digital Comic Museum at http://www.digitalcomicmuseum.org/index.php?dlid=23784)