Chimerarachne yingi

Overview

Chimerarachne yingi is a long-tailed arachnid closely related to spiders. Its distinctive combination includes four pairs of walking legs, silk-producing organs, and a tail. Imagining it alongside a familiar spider makes body differences clear.^[1]

Key facts

A long tail extends behind the eight walking legs. It bears ring-like segments, and male palps are described separately from the walking legs. Distinguishing each type of appendage makes an initially complex body readable.^[1]

Time and place

It was described from amber fossils from the Hukawng Valley in present-day Kachin State, Myanmar. A 2018 study presented this as mid-Cretaceous material approximately 100 million years old. A body preserved in tiny amber reveals the arrangement of an ancient spider relative.^[1][2]

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

Size, form and skeleton

The front and rear body connect narrowly, and the abdomen is described as segmented with silk-producing organs underneath. A long tail with ring-like segments extends behind it. Four pairs of walking legs can be distinguished from separate palps.^[1]

The Museum für Naturkunde in Berlin describes this small arachnid’s body as approximately 2.5 mm long. Its whip-like tail extended farther than the body’s length.^[3]

The museum account gives a tail length of approximately 3 mm. Separating body length from tail length reveals its distinctive proportions.^[3]

Habitat and reproduction

Silk-producing organs beneath the abdomen provide an important feature for comparison with spiders. A long tail and segmented abdomen are also preserved, revealing a combination of different body regions. This organism raises questions about the emergence of features composing a familiar spider body.^[1]

Fossil discovery

A 2018 study described the animal using male specimens NIGP166870 and NIGP166871. The tail lacking its tip in the reference specimen could be compared with a complete tail in the other specimen. The two fossils thus reveal different body parts.^[1]

References

1. Wang et al. (2018) — Long-tailed Chimerarachne
2. International Commission on Stratigraphy (2024) — Geological time chart
3. Museum für Naturkunde Berlin (2017–2018) — The tailed arachnid Chimerarachne
4. Dunlop (1999) — A redescription of Plesiosiro
5. Selden·Dunlop (1998) — Morphology and relationships of fossil spiders

Research questions

How are relationships assessed when a spider-like body also has a long tail? Walking legs, palps, silk-producing organs, and abdominal segments are compared together. This shows why combinations of structures, rather than one feature alone, matter in evolutionary research.^[1]

Observation

After identifying four pairs of walking legs, locate the palps near the head and the long tail behind the body separately. Imagining the silk-producing organs beneath the abdomen makes the unusual combination clearer.^[1]