Pseudopulex jurassicus

Overview

Pseudopulex jurassicus is a wingless Jurassic insect resembling a flea. Its elongated body, three pairs of slender legs, and long serrated mouthparts catch the eye. One small fossil raises large questions about the bodies and feeding habits of insects in the age of dinosaurs.^[1]

Key facts

Type specimen CNU-NN2010001 was reported as 17 millimeters, about 1.7 centimeters, long excluding the antennae. Its long, robust mouthparts measured at least 3.44 millimeters. Reading body and mouthpart measurements together in one individual makes this insect’s unusual proportions around its small head clearer.^[1]

Time and place

A 2012 study introduced this fossil as a record from about 165 million years ago, near the end of the Middle Jurassic. The locality is the Jiulongshan Formation at Daohugou, Ningcheng County, in present-day Inner Mongolia, China. The formation addressed in the paper also preserves several feathered dinosaurs, pterosaurs, and small mammals, evoking the terrestrial world of the time.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

Short, bead-segmented antennae lie on either side of the small trapezoidal head. A long abdomen follows a small thorax, and a pair of sickle-shaped claws was described at the ends of the long, slender legs. Backward-pointing body bristles and comb-like structures on the tibiae also attracted the researchers’ attention.^[1]

Habitat and reproduction

Considering serrated mouthparts, curved claws, and body bristles together, researchers proposed that it may have attached to other animals and fed on blood. They inferred gripping feathers or fur and piercing tough skin from body structure. Which animals it used is an intriguing question beginning with this small insect’s mouth and legs.^[1]

Fossil discovery

In 2012, researchers named the species from a nearly complete fossil viewed ventrally. The genus name Pseudopulex conveys resemblance to fleas, and the species name jurassicus refers to the Jurassic. They distinguished it from another, Cretaceous species in the same paper by comparing antennae, mouthparts, and tibial structures.^[1]

References

1. Mid-Mesozoic Flea-like Ectoparasites of Feathered or Haired Vertebrates
2. Lin et al. (2016) — Reading Jurassic insects through long proboscises and wing veins

Research questions

If it looked like a flea, did it jump in the same way? The paper explains that it lacked the specialized jumping hind legs of living fleas and was not laterally flattened. Comparing similar mouthparts alongside different legs and body forms reveals ways to explore the life and relationships of an ancient flea-like insect.^[1]

Observation

The illustration examines the arrangement of a small head, long abdomen, and six legs based on the ventral view of the type specimen. Find the long mouthparts extending rearward beneath the head and the curved claws at the leg tips in sequence. Some leg tips were completed using anatomical descriptions of the same species, and colors and shading were used to make the form easier to read.^[1]