Cape Razorfish, Xyrichtys mundiceps
The Cape Razorfish, Xyrichtys mundiceps, whose common Spanish name is cuchillo desnudo, is a member of the Wrasse or Labridae Family, known collectively as doncellas, señoritas, and viejas in Mexico. Globally, there are twenty-seven species in the genus Xyrichtys, four of which are found in Mexican waters, three in the Atlantic and one in the Pacific.
The Cape Razorfish have strongly compressed heads and bodies that taper gradually from head to tail and have a depth that is 30 to 39% of standard length. Initial Phase (IP) females are uniformly pale brown and often have a prominent white patch over their abdomen. Terminal Phase (TP) males are darker brown with a narrow blue vertical line on each scale and a large black spot at the base of their caudal fin above the lateral line. They also have three concentric blue lines on the outer part of their gill covers and three narrow blue lines running obliquely from their eye across their cheek. Their lower jaw and the lower side of their head have blue stripes and lines. All fish have pale fins. Their head is large and 25% of total length; it has a steep profile and a longitudinal keel at the front. Their eyes are set on the upper half of the head and both jaws have canines at the front. TP males have a steeper forehead and deeper body than females. Their anal fin originates under the last dorsal spine; their caudal fin is slightly convex; their dorsal fin is continuous with nine spines and eleven rays; their pectoral fins reach the anal fin origin; and their pelvic fins are strongly pointed with an elongated first ray.
The Cape Razorfish are normally found half buried on the bottom within fine sand at depths between 20 and 90 feet. They reach a maximum length of 15.9 cm (6.3 inches). They are a rare and poorly studied species and very little is known about their behavioral patterns.
In Mexican waters the Cape Razorfish has a limited distribution being found from Magdalena Bay southward along the southwest coast of Baja, from Loreto southead along the east coast of Baja, and from Acapulco southward along the coast of the mainland.
The Cape Razorfish is an easy fish to identify due to its unique markings, however, it can be confused with the Peacock Razorfish, Iniistius pavo (no tail spot; separate and elongated first dorsal spine).
The Cape Razorfish are too small and too rare to be of interest to most.
Cape Razorfish, Xyrichtys mundiceps, terminal phase (TP) male. Fish caught off the beach at Playa Tecolote, La Paz, Baja California Sur. Length: 10.0 cm (3.9 inches). Catch, photo and identification courtesy of Dr. Benjamin Victor, www.coralreeffish.com.
Cape Razorfish, Xyrichtys mundiceps, initial phase (IP) female. Fish caught off the beach at Playa Tecolote, La Paz, Baja California Sur. Length: 12.0 cm (4.7 inches). Catch, photo and identification courtesy of Dr. Benjamin Victor, www.coralreeffish.com.
Cape Razorfish, Xyrichtys mundiceps, juvenile. Fish caught off the beach at Playa Tecolote, La Paz, Baja California Sur. Length: 15.0 cm (5.9 inches). Catch, photo and identification courtesy of Dr. Benjamin Victor, www.coralreeffish.com.