G. admarinus grows to about 25millimeters in length and has around 47 legpairs. It's characterized by a head longer than it is wide; first maxillae with palpus and inner process both conically pointed and each having typically 5 setae on its ventral face; smoothclaws of the second maxillae; concave labrum; mediandivision straight or slightly concave, bearing 5 long, basally dark teeth, and lateral division pectinate; syncoxite bearing a lappet on each side; coxae broadlyunited with no trace of a median suture; unarmed prosternum of poison claws with an absence of chitin lines and minute teeth at the base; and an absence of ventral pores.