Background

In comparison to other crustacean groups, brachyuran crabs have been well studied in the Persian Gulf (Stephensen, 1946; Apel, 2001; Titgen, 1982; Naderloo & Sari, 2007; Naderloo & TĂĽrkay, 2012). The family Xanthidae is one of the most common families in the region. Apel (2001) listed 22 xanthid species from the Gulf, of which five were new records to the region. Naderloo & TĂĽrkay (2012) added Macromedaeus voeltzkowi (Lenz, 1905) and two new species of Palapedia Ng, 1993, were recently described by Naderloo (2015). The Pilumindae is another common family in the region and represented by 23 species in the Persian Gulf (Apel, 2001; Naderloo & TĂĽrkay, 2012). One more species, namely Cryptopilumnus pereiodontus (Davie and Ghani, 1993) is added in this study.

Methods

The biodiversity project is concentration on four main taxa of Abu-Musa Island: Crustacea, Mollusca, Polychaeta and Echinodermata. Sites sampled were intertidal and shallow subtidal habitats around the whole Island. The tidal range along the coast of the Island is low at around two meters (2.25 m recorded during spring tide), therefore the tidal zones, in comparison to other part of the Persian Gulf, are not exposed during the low tide and sampling has been mainly undertaken by snorkeling. Specimens have been preserved in Ethanol 75 % and shipped to the University of Tehran and the material was deposited in the Zoological Museum, University of Tehran (ZUTC) where it is available for further examination.

Results and discussion

Order DECAPODA Latreille, 1802

Superfamily XANTHOIDEA MacLeay, 1838

Family XANTHIDAE MacLeay, 1838

Atergatis integerrimus (Lamark, 1801)

(Fig. 1)

Fig. 1
figure 1

Atergatis integerrimus (Lamark, 1801). Male (ZUTC 5483), CL = 34.88, CB = 56.21 mm, Park-Qadir, Abu-Musa Island, Persian Gulf, 25.12.2014, Photo credit: R. Abdollahi

MATERIAL EXAMINED: 1♂ (ZUTC 5483), CL = 34.88, CB = 56.21, Park-Qadir, Abu-Musa Island, Persian Gulf, 25° 53.751′N, 055° 02.643′E, rocky/cobble, taken by snorkeling, coll. S. Ebrahimnezhad & R. Abdollahi, 25.12.2014.

TYPE LOCALITY: Australia.

REGIONAL RECORDS: Stephensen (1946) recorded the species from Larak Island in the Iranian territory and Apel (2001) from UAE in the Gulf of Oman.

DISTRIBUTION: Zanzibar, Persian Gulf, Gulf of Oman, Strait of Hormuz, Pakistan, South India, Taiwan, Philippines and Japan.

REMARKS: Three species of Atergatis have been recorded from the region, A. laevigatus A. Milne-Edwards 1865, A. integerrimus, and A. ocyroe (Herbst, 1801). The two latter species have not previously been recorded from the inner Gulf.

Macromedaeus crassimanus (A. Milne-Edwards, 1867)

(Fig. 2)

Fig. 2
figure 2

Macromedaeus crassimanus (A. Milne-Edwards, 1867). Male (ZUTC 5477), CL = 21.47, CB = 34.36 mm, Park-Qadir, Abu-Musa Island, Persian Gulf, 29.12.2014. Photo credit: R. Abdollahi

MATERIAL EXAMINED: 2♂ (ZUTC 5477), CL = 18.14–21.47, CB = 28.51–34.36 mm, Park-Qadir, Abu-Musa Island, Persian Gulf, 25° 53.751′N, 055° 02.643′E, rocky/cobble, corals, by snorkeling, coll. S. Ebrahimnezhad & R. Abdollahi, 29.12. 2014.

TYPE LOCALITY: New Caledonia.

REGIONAL RECORDS: This is the first record of the species from the Persian Gulf, furthermore there is no report of this species from the Gulf of Oman.

DISTRIBUTION: Red Sea, Persian Gulf, Pakistan, India, Sri Lanka, Andaman Islands, Taiwan, China, Indonesia, Sumatra, Palau, Christmas Islands, Australia and New Caledonia.

REMARKS: Macromedaeus is represented by three species from the region namely M. crassimanus, M. quinquedentatus (Krauss, 1843), and M. voeltzkowi (Lenz, 1905). The two latter species have been recorded from the Gulf of Oman by Ghotbeddin & Naderloo (2014), but this is the first record of M. crassimanus for the region.

Zosimus aenus (Linnaeus, 1758)

(Fig. 3)

Fig. 3
figure 3

Zosimus aeneus (Linnaeus, 1758). Female (ZUTC 5479), CL = 44.10, CB = 64.39 mm, Park-Qadir, Abu-Musa Island, Persian Gulf, Persian Gulf, 22.12.2014. Photo credit: R. Abdollahi

MATERIAL EXAMINED: 1♂ (CL = 26.03, CB = 37.25 mm), 2♀ (CL = 25.76–44.10, CB = 38.23–64.39) (ZUTC 5479), Park-Qadir, Abu-Musa Island, Persian Gulf, 25° 53.751′N, 055° 02.643′E, rocky/cobble, by snorkeling, coll. S. Ebrahimnezhad & R. Abdollahi, 22–29.12.2014.

TYPE LOCALITY: East India.

REGIONAL RECORDS: This is the first Persian Gulf record of the species, however there are no records from the neighboring regions of Arabian coast, Gulf of Oman and Pakistan.

DISTRIBUTION: South Africa, Madagascar, RĂ©union, Mayotte, Seychelles, Tanzania, Mozambique, Somalia, Red Sea and Persian Gulf.

Zozymodes cavipes (Dana, 1852)

(Fig. 4)

Fig. 4
figure 4

Zozymodes cavipes (Dana, 1852). Female (ZUTC 5478), CL = 14.19, CB = 20.39 mm, Park-Qadir, Abu-Musa Island, Persian Gulf, 23.12.2014. Photo credit: R. Abdollahi

MATERIAL EXAMINED: 1♂ (CL = 11.84, CB = 17.74), 3♀, (CL = 9.76–14.19, CB = 14.77–20.39 mm) (ZUTC 5478), Park-Qadir, Abu-Musa Island, Persian Gulf, 25° 53.751′N, 055° 02.643′E, rocky/cobble, by snorkeling, coll. S. Ebrahimnezhad & R. Abdollahi, 23–26.12.2014.

TYPE LOCALITY: East India.

REGIONAL RECORDS: This is the first record of this species from the Persian Gulf and there are no records from the Gulf of Oman.

WORLD DISTRIBUTION: East Africa, Madagascar, Aldabra Islands, Red Sea, Gulf of Aden, Persian Gulf, Gulf of Oman, Pakistan, Andaman Islands, Chagos Archipelago, Mergui Archipelago, Malaysia, Indonesia, Taiwan, China, Japan, Christmas Island and Australia.

REMARKS: Zozymodes xanthoides (Krauss, 1843) is a common species in the rocky/cobble intertidal habitats along the northern Indian Ocean including the Persian Gulf and the Gulf of Oman, while Z. cavipes is a comparatively rare xanthid in the region. This species has already been listed under the known species of Xanthidae from the Persian Gulf by Guinot (1967) and Titgen (1982), but the provenance for their record is uncertain.

Superfamily PILUMNOIDEA MacLeay, 1838

Family PILUMNIDAE MacLeay, 1838

Cryptopilumnus pereiodontus (Davie & Ghani, 1993)

(Fig. 5)

Fig. 5
figure 5

Cryptopilumnus pereiodontus (Davie & Ghani, 1993). Female (ZUTC 5480), CL = 3.76, CB = 4.90 mm, Park-Qadir, Abu-Musa Island, Persian Gulf, 31.12.2014. Photo credit: R. Abdollahi

MATERIAL EXAMINED: 5♂, 9♀ (ZUTC 5535), Park-Dowlat, Abu-Musa Island, Persian Gulf, rocky/cobble intertidal, coll. R. Naderloo, S. Ebrahimnezhad & R. Abdollahi. 29.04.2014; 1♀ (ZUTC 5535), Park-Qadir, Abu-Musa Island, Persian Gulf, coll. S. Ebrahimnezhad & R. Abdollahi, 31.12.2014; 3♂, 7♀ (ZUTC 5480), Park-Qadir, Abu-Musa Island, Persian Gulf, rocky/cobble intertidal, coll. S. Ebrahimnezhad & R. Abdollahi, 25.04.2014.

TYPE LOCALITY: Pakistan.

REGIONAL RECORDS: This is the first record of the species from the Persian Gulf, while there is no record from the Gulf of Oman.

DISTRIBUTION: Persian Gulf and Pakistan.

REMARKS: Cryptopilumnus pereiodontus was originally described from Karachi in Pakistan and referred to Pilumnopeus A. Milne-Edwards, 1867, but Hsueh et al. (2009) assigned this species to Cryptopilumnus. The genus is distinguishable from Pilumnopeus by the merus of walking legs having distinct denticles on the posterior margin.

Conclusion

The families Xanthidae and Pilumnidae are among the most diverse intertidal crabs in the region (Apel, 2001; Naderloo & Türkay, 2012; Naderloo et al. 2015). The four xanthid records recorded by the present study increases recognised Xanthidae species in the Persian Gulf to 29 (Table 1). Cryptopilumnus pereiodontus (Davie & Ghani, 1993) collected from the Abu-Musa Island, is a new pilumnid record for the Persian Gulf and increasing the number of recognised species of the Pilumnidae in the Persain Gulf to 24. The number of species from both families are probably still underestimated, and this is partly due to complex taxonomy of the two taxa.

Table 1 Brachyuran crabs of the family Xanthidae currently recorded from the Persian Gulf. References for every record are provided in the table, precise locality not indicated