By Jean Balchin 13/12/2017

A 99 million-year-old fossil found in Myanmar has revealed that out feathered dinosaurs were riled with ticks just like modern animals. The team of European researchers, lead by Ricardo Pérez-de la Fuente from the Oxford University Museum of Natural History, unearthed the ticks found several specimens in pieces of amber, including one entangled with a dinosaur feather, another engorged with blood and others near a dinosaur nest. According to the researchers, there is more than enough evidence to indicate that these ticks fed on feathered dinosaurs.

Hard tick photographed at Cabañeros National Park, Spain. E. Peñalver.

What are ticks?

Ticks are ectoparasites (external parasites), living off the blood of mammals birds and occasionally, reptiles and amphibians. Ticks are scientifically classified as Arachnida, and there are a variety of tick-borne diseases. Ticks had evolved by the Cretaceous period (the last of the three periods of the Mesozoic Era, from 145.0 million years ago to 66 million years ago). These creepy-crawlies are currently among the most prevalent of blood-feeding ectoparasites but not much is known about their feeding habits and hosts in deep time.

Studied tick pieces and extant hard tick for comparison (tick is 5 mm long). E. Peñalver

Hard Ticks and Soft Ticks

According to Orkin, hard tick adult males and females have different coloration and females are somewhat larger than males. Moreover, hard ticks possess a kind of plate on their back, called a scutum, and mouthparts that are visible when the tick is viewed from above. In contrast, soft ticks appear to have a wrinkled body; lack a scutum; and the males and females are very close to the same size.

“Viewing a soft tick from above would give someone the impression that soft ticks do not have mouthparts. However, that is not the case; rather their mouthparts are located on the underside of the body so that the front portion of the tick’s body hides the mouthparts.”

The research team found direct and indirect evidence in 99 million-year-old Cretaceous amber shows that hard ticks and ticks of the extinct new family Deinocrotonidae fed on blood from feathered dinosaurs, non-avialan or avialan excluding crown-group birds.

Specimens include a

  • †Cornupalpatum burmanicum hard tick entangled a pennaceous feather.
  • Two deinocrotonids described as †Deinocroton draculi gen. et sp. nov. have specialised setae from dermestid beetle larvae (hastisetae) attached to their bodies, likely indicating cohabitation in a feathered dinosaur nest.
  • A third conspecific specimen was blood-engorged, its anatomical features suggesting that deinocrotonids fed rapidly to engorgement and had multiple gonotrophic cycles.

These findings provide insight into early tick evolution and ecology, and shed light on poorly known arthropod–vertebrate interactions and potential disease transmission during the Mesozoic period.

These findings shed light on early tick evolution and ecology, and provide insights into the parasitic relationship between ticks and ancient relatives of birds, which persists today for modern birds.

The study was published in Nature Communications this week.