Strange (Sea)Bedfellows - Observation of the Week, 11/8/22

Our Observation of the Week is this Urchin Carrier Crab (Dorippe frascone) carrying a Blue-spotted Urchin (Astropyga radiata)! Seen in The Philippines by @albertkang. 

Originally from Malaysia, Albert Kang has been living in The Philippines since 2002. In 2006 he stopped working and got into scuba diving, which reignited his long-held interest in nature. “Scuba diving,” he says, “opens up a whole new world of underwater marine life and was fascinated with it.”

When some friends from Belgium recently came to visit him, they went diving at Anilao, Batangas, Philippines, where Albert dives regularly.  “A Filipino friend owns a dive resort there and I go there very regularly and also bring friends from other countries to dive there :D,” he tells me.

Usually, this crab is only active at night but this dive was during a bad weather day and by 5 pm, it was already getting dark underwater.  The dive was at a muck dive site, meaning sandy bottom. The crab was scurrying around, carrying the sea urchin, which is always interesting to see since the crab by itself is drab in colour and not too interesting/exciting.  The bright colours of the sea urchin make it stand out, in addition to the interesting symbiotic relationship behaviour.

A small species (its carapace grows to about 5 cm (2 in)), the urchin carrier crab often uses its rear two pairs of legs to hold an urchin, leaving its two front non-pincer legs free for walking. It’s thought the urchin provides protection for a crab, and the crab brings it to new areas to feed, benefiting both partners.

“I am more of a generalist,” says Albert (above, taking a selfie with a Wallace’s Flying Frog in Malaysia), “meaning I take pictures of most things but more on the smaller stuff for macro photography. The joy is more of ‘searching’ and ‘finding’ tiny critters that are often overlooked and seldom photographed.” He joined iNat over seven years ago and tells me that after doing so  “I am spending more time out in the field to take pics and looking for new stuff.”

- Two phasmids have been described based Albert’s photos: Orthomeria kangi, from Philippines in 2016, and Orthonecroscia keatsooni from Malaysia in 2016. Albert tells me several more species are currently being described, based on his findings.

-  Cool footage of an urchin carrier crab and its buddy.

Posted on November 8, 2022 08:06 PM by tiwane