Static Route / predefined variables

I am trying to setup a route that sets a fixed parameter

PHP Code:

$routes->get('/', 'Pages::showme/first');
$routes->get('pages/showme/(:alphanum)', 'Pages::showme/$1'); 


hitting "/" results in

Code:

Controller method is not found: showme\first

But "/pages/showme/first" works as expected

I have read the route manual but have not found a way to do it, any help is greatly appreciated