Calcinus hazletti Haig & McLaughlin 1984

Fig. 2c

Material. 1 juvenile, shield length (SL) 1.58 mm (UF 7075), Saipan Island, station NM-05 [identification tentative] ; 2 specimens (UF 7076), Sarigan Island, station SAR-002 ; 2 specimens (UF 5739), Alamagan Island, station ALA-003 ; 2 specimens (UF 5736), Pagan Island, station PAG-01 ; 1 specimen (UF 5732), Pagan Island, station PAG-07 ; 1 specimen (UF 5729), Agrihan Island, station AGR-02 ; 2 specimens (UF 5738), Agrihan Island, station AGR-04 ; 4 specimens (UF 5741), Asuncion Island, station ASU-02 ; 3 specimens (UF 5731), Asuncion Island, station ASU-03 ; 1 specimen (UF 5733), Maug Islands, station MAUG-01 ; 5 specimens (UF 5740), Maug Islands, station MAUG-02 ; 4 specimens (UF 5730), Maug Islands, station MAUG-02 ; 1 specimen (UF 7074), Maug Islands, station MAUG-03 ; 1 specimen (UF 5735), Maug Islands, station MAUG-04 ; 1 specimen (UF 5734), Maug Islands, station MAUG-06 ; 3 specimens (UF 5737), Maug Islands, station MAUG-06 ; 2 specimens (UF 5725), Maug Islands, station MAUG-10 ; 3 specimens (UF 5726), Maug Islands, station MAUG-11 ; 1 specimen (UF 5727), Stingray Shoal station STI-001 ; 1 specimen (UF 5723), Stingray Shoal, station STI-002 ; 1 specimen (UF 5728), Uracas Island, station URA-002 .

Remarks. Common in the intertidal area of the Northern Marianas. There is one questionable record from Saipan (UF 7075), however it is a juvenile and cannot be identified with confidence. Even if UF 7075 is indeed C. hazletti, the species is exceedingly rare in the Southern Marianas. This species is otherwise only known from Hawaii and Japan (Haig & McLaughlin 1984; Asakura & Tachikawa 2003; Arima 2004). However, the Northern Mariana population is genetically distinct from the Hawaiian population (Malay & Paulay 2010). Given the genetic evidence and disjunct distribution, it is possible that the Northern Marianas and Japanese form represents a cryptic species.