The Sorting Hat

Above shows a piece of The Daily Mail newspaper used as stuffing for one of the specimen boxes, dated June 24, 1908. At the time I’m sure this was just an un-important, unused piece of newspaper but the history it shows now is very interesting!

I will be updating this blog on a weekly basis, as this is how frequently I visit the museum to get some work done. This week I was mainly sorting through and selecting 10-15 crustacean specimens (hence the HP reference of the sorting hat) that I could use at the museums event day, where I will be sat next saturday with my table and my lovely crabs!

I am going to share with you some photographs of the crabs and lobsters that I came across yesterday, and give you a little description about the species and (where available) its habitat and common name.

As with before, I am a complete novice at this, so am just using internet and books to find this information, coupled with a little too much trust in the names written on the specimens (they are quite often wrong or incomplete!), so please do leave comments if you see something that should be changed!

The main book used in this post will be cited as Debelius, 2001, referring to Debelius, H. (2001) Crustacea Guide of the World, Germany, IKAN.

Hope you enjoy.

Calappa flamea or ‘Flame Box Crab‘ has a width of up to 11cm, and a carpasce length up to 8cm. It is similar to its relative calappa ocellata but can be distinguished by its distinctive network of lines which continue onto the posterior part of the carpace, whereas in C. ocellata, it fades out. They are part of the group “box crab”, a common name is also the shame-faced crab as they hold their claws up in front of their faces as if hiding (Debelius, 2001). I have also found a very interesting paper (Dietl, G.P. & Hendricks, J.R. (2006) Crab scars reveal survival advantage of left-handed snails, Biology Letters, 2(3): 439–442) which explains that box crabs like this one are right-handed. They use their front left claw to hold the snail, and use their right to cut the shell along its spire, and then the crab can conveniently eat its prey. Dietl and Hendricks found that snails with shells that are “left-handed” are at an advantage from predators such as the box crab, because they are disguarded as not worth it!

2. Carcinoplax longimana (de Haan, 1835) Arthropoda, Crustacea, Decapoda, Goneplacidae, Carcinoplax, Longimana

This is not in my book, but I have had a look online and looks to me like this species is supposed to be a red colour in life, and had cheliped (claw-bearing appendage, terminating in a chelae or a pincer), white fingertips. They generally live in sand, mud or shelly substrates at depths of 30-820 m. (Biota Taiwanica)

3. Dardanus guttatus, common name ‘Blue Knee Hermit Crabs’, live in conditions of 22°C – 28°C and grows up to 10cm. They are carnivores and active hunters of snails, clams and other small invertebrates including small fish. As a hermit crab, when D. guttatus grows, it moves to bigger, more suitable shells and can grow to the size of a tennis ball. (Reeflex)

4. Dromia excavata is shown above. I think this is a sponge crab (see point 5.), but was more interested in its friend. This crab has something stuck to the top of its shell. I am not sure what it is, but have seen accounts of D. excavata being found in commensal association with a compound ascidian, so this may be the case. Ascidians are commonly known as sea squirts, and are marine filter feeders known for attaching to shells of crabs and other crustacea.

5. Dromia glohosa (Lamarck, 1818) is shown here with pieces of material next to each crab. I have not seen this grouping behaviour in any of the specimens yet (except for D. excavata). Similarly with D. excavata, Dromia refers to a crab of the Dromiidae family, commonly known as sponge crabs. Almost all dromiids carry with them a piece of living sponge, ascidian (sea squirt as mentioned above), soft coral or shell held in position over their backs by their last two pairs of legs. I believe that in this specimen, the pieces of material are what the crabs may have been found attached to, and therefore they may have been carrying it. It is quite usual for them to carry living things much bigger than their carpace, as this is good camouflage. (Debelius, 2001)

This is all for this post, but I shall continue researching and update the blog with any more findings. Still to come is information on the following:

Halimus truncatipes

Hyas araneus

Ibacus antarcticus

Liocarcinus marmoreus

Ilia nucleus

Leucosia unidentata

Ocypoda ceratophthalma

 

Squilla mantis

Thenus orientalis

S. Squamifera quernsiy

Podophtalmus vigil

Pinnotheres pisum

Pilumnus hirtellus

Panulirus guttatus

Pagurus bernhadti 

Ocypode arenaria

Macropodia rostrata

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