Species of dinosaur with longest fossile record (no birds!)
Dinosaur biostratigraphy makes it not possible to answer your question through all of history. 8Ma is the highest longevity species I found in a biostratigraphy table. Dinosaurs are faster evolving than crocodilians who have 1/3rd as big a genome as a mouse and 1/6th that of a shark. Adaptive genus existed for 5-30 million years, and well known clades exist for 20-500 Ma.

 

The most complete geological formations often only cover small spans of history. Generally you will find that paleontologists have few species, and more often groups and genus represented by 10-20 species fragments.

The Hell Creek Formation covers 2 million years of history, and has revealed 400 species, of turtles, dinosaurs, metatherians, mammals, turtles, and a very rich image of life at that time, and 90 percent of the geological time scale is represented by only a fragments of fossils. 

So, you won't find a good answer for species, perhaps the best way to find out the longest lived genus (i.e. like a dragonfly, all species are in the same family) is by doing some google tricks: 

For genus i can find this: 

Plateosaurus 214–204 Ma

Thyreophorans group 199.6–66 Ma

Gryposaurus genus  84-73 Ma

Plesiosaurus genus 199.6–175.6 Ma

Gorgonopsians 265–252 Ma

Dimetrodon 295–272 Ma

Carcharodontosaurus 112-93

Pterosaur 228–66 Ma

Mussaurus : 215–203 Ma

Lesothosaurus : 199–189 Ma

Spinosaurus : 112-93

Kronosaurus genus 125–99 Ma

scorpion 430–0 Ma.

Dragonfly     325–0 Ma

brittle star 499Ma-present

crocodilians 200-0

some shark genus: 100-0

snapping tortoise 100-0

horeshoe crab 455-0

nautilus 488-0

Fossil fields are incomplete, so the HellCreek time period is very well represented with lots of tyranosaurus, and other time periods are incomplete.

Animals with small genotypes Crocodiles and turtles evolve very slowly, and it gives you an idea of evolution speeds prior to the arrival of mammals, who seem can adapt faster than all previous larte animals. 

crocodiles have less than 1/3 of the genes of a mouse and a human
tortoises have 2/3rds and so do horseshoe crabs
dragonfly have 1/6th the genome size of a mouse
sharks have twice as big genome