APHOTOMARINE

An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.

A-P-H-O-T-O Wildlife Stock Image Library
Achaeus cranchii Leach, 1817 - Cranch's spider crab (Crustaceans)
Spider crab
Achaeus cranchii
- with 0.1mm rule 1

Spider crab
Achaeus cranchii
- dorsal view 1

Spider crab
Achaeus cranchii
- dorsal view carapace 1

Spider crab
Achaeus cranchii
- tuberculed eye pair 1

Spider crab
Achaeus cranchii
- tuberculed eye 1

Spider crab
Achaeus cranchii
- claws 1

Spider crab
Achaeus cranchii
- claw of hind leg 1

Specimen above found by the author under a rock on an extra low tide at Hannafore, Cornwall, 30.03.2017.

Spider crab
Achaeus cranchii
- dorsal view / in-situ 1

Specimen above found by the author under a rock on an extra low tide at Hannafore, Cornwall, 01.02.18. The above was one of three specimens found that day.

Typical dimensions of male carapace 11mm x 9mm. Possibly overlooked as the species appears similar to a juvenile Macropodia rostrata, most of the identification features may be hidden, but the lack of a rostrum, eye pair with tubercules and the toothed hinds claws are quite distinctive.

Please note, Spider crabs can be quite tricky to identify with any certainty because of a covering of algae. This means verification from images may be impossible. It may be necessary to remove some of the algae with fine tweezers in order to identify weed covered specimens using a stereomicroscope and key. It is too easy to assume specimens are the common Macropodia rostrata, when they may not be, and detailed examination is important if under-recorded species are to be found and identified.

APHOTOMARINE supports open source data recording and sharing for the benefit of wildlife, recorders, research, science and education. The project recommends the following websites and works with the following bodies and organisations.

Marine Biological Association MBA

The Marine Biological Association or MBA, based in Plymouth, is one of the world’s longest-running societies dedicated to promoting research into our oceans and the life they support. Since 1884 the MBA has been providing a unified, clear, independent voice on behalf of the marine biological community.It has a growing membership in over 40 countries.

NBN National Biodiversity Network

The National Biodiversity Network or NBN is a charity that supports open source data sharing and recording supporting conservation, science and education. "Why do recorders need open source?". Simply because it supports the core values of wildlife recording and the free use of records and data over a very wide network that includes partners like the Natural History Museum.

The taxonomy used here is based on that of the following database, which is also used by the MBA, NHM and the NBN.

World Register of Marine Species or WoRMS

The World Register of Marine Species or WoRMS.

Achaeus cranchii Cranchs spider crab Crustacean Images
The main objective of this website is in furthering environmental awareness and education through the medium of photography. To increase awareness and access to the wildlife of the region and help
people find and identify it. Sometimes the difference between species is obvious but many species can only be determined by observing microscopic characteristics that are specific to any one species.