Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Austruca perplexa
open-in-new
<p><i>Austruca perplexa</i> is a <a href="/facts/Species/oDg6b96r">species</a> of <a href="/facts/Fiddler_crab/orSD3FKF">fiddler crab</a>. It is found from the <a href="/facts/Ryukyu_Islands/94rjkv8f">Ryukyu Islands</a>, <a href="/facts/Japan/U5mz0SRT">Japan</a> to <a href="/facts/India/1kKHcnxM">India</a>, throughout the <a href="/facts/Malay_Archipelago/RkeF5zR1">Malay Archipelago</a>, along eastern <a href="/facts/Australia/qLHpbppq">Australian</a> coasts from <a href="/facts/Queensland/lXBlIeY3">Queensland</a> to <a href="/facts/New_South_Wales/aW7eJXSS">New South Wales</a>, and in various <a href="/facts/Pacific_islands/AxJ5sXWp">Pacific islands</a>, including <a href="/facts/Fiji/JU8Hs8WH">Fiji</a>, <a href="/facts/Tonga/oX5vwTer">Tonga</a> and <a href="/facts/Vanuatu/ta20UNlL">Vanuatu</a>. </p><p><i>Austruca perplexa</i> was formerly in the genus <i><a href="/facts/Uca/orSD3FKF">Uca</a></i>, but in 2016 it was placed in the genus <i><a href="/facts/Austruca/jI3aNSAg">Austruca</a></i>, a former subgenus of <i>Uca</i>. </p><p>As in other fiddler crabs, the male has a greatly enlarged claw, which is used for <a href="/facts/Signalling_theory/mfkQtxBo">signalling</a>. The higher the claw is waved by the male, the greater his chance of attracting a female; the size of the claw is therefore subject to <a href="/facts/Sexual_selection/AjDd8Tam">sexual selection</a>. Furthermore, larger male fiddler crabs wave their claws at a faster rate than smaller fiddler crabs to attract larger females. Larger females are more desirable because they produce more eggs than smaller females. </p> <p><i>Austruca perplexa</i> is usually found on sandy substrates near river mouths or on sheltered beaches in the mid-intertidal zone, usually near mangroves.</p>