Adelophthalmus granosus

Overview

Adelophthalmus granosus is a Late Carboniferous eurypterid known from several segments of the rear body. The type specimen preserves the rear of the anterior carapace and segments continuing behind it. Repeating body segments reveal the construction of an ancient arthropod.^[1]

Key facts

The first through ninth opisthosomal segments can be identified in type specimen MB.A.890. Researchers compared these preserved regions with the form of related groups. A limited area of preservation connects to the construction of a larger body.^[1]

Time and place

It is known from research redescribing Late Carboniferous adelophthalmids. The Carboniferous as a whole was roughly 360–300 million years ago. The study compared forms while distinguishing type specimens of different species.^[1][2]

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

Size, form and skeleton

The reference material includes the rear of the prosomal carapace followed by a segmented opisthosoma. The author’s composite form considers these species-specific parts alongside general adelophthalmid construction. Genus-level comparisons also include paddle-shaped appendages and a long telson.^[1]

In 2005, researchers reconstructed Adelophthalmus granosus at about 15cm in total length based on body proportions and surface ornament. This is the size of a reconstruction combining the preserved fossil with the group’s general body construction.^[3]

Habitat and reproduction

How did appendage shapes differ within the same body? The genus-level description distinguishes spiny appendages from a paddle-shaped sixth appendage. Examination of body segments continues alongside comparisons of appendage construction.^[1]

Fossil discovery

The redescription rechecked the body segments actually preserved in MB.A.890. MB.A.889, a comparative specimen of another species, was treated separately. This study organized species-specific evidence by examining old fossils anew.^[1]

References

1. Redescription study — Body and specimens of Adelophthalmus
2. International Commission on Stratigraphy (2024) — Geological time chart
3. Tetlie·Dunlop (2005) — Reassessment of Adelophthalmus granosus and zadrai
4. Selden et al. (2005) — The identity of Megarachne, once thought to be a giant spider

Research questions

When only part of a body remains, how can the rest be studied? The author separately compared the proportions and ornament preserved in the species with the construction of the same group. This encourages consideration of which questions the preserved regions and comparative material each answer.^[1]

Observation

Follow the segments continuing behind the anterior carapace in sequence. Examining the repeating body regions, broad appendages, and long telson separately reveals both the major construction and partial features.^[1]