Family SESARMIDAE Dana, 1851

Selatium brockii [Davie 2002: 220 (modified from de Man 1888: pl. 16 fig. 3)]

Museums

Regional Maps

• Sesarminae Dana, J.D. 1851. On the classification of the Crustacea Grapsoidea. American Journal of Science and Arts 12: 283-290 [288].

Introduction

The Sesarminae, comprises mostly semiterrestrial species that have conquered middle to high intertidal mangrove and estuarine environments. These crabs are largely herbivorous and appear to play a significant role in energy cycling in mangrove systems by consuming vast quantities of fallen leaves and young seedlings. In addition, their burrows help to aerate the soil, particularly around the root systems of the trees (Robertson 1991; Smith et al. 1991). Davie (1985, 1994) discussed the distribution patterns of intertidal mangrove crabs across northern Australia, including sesarmines.

Excluded Taxa

Misidentifications

SESARMIDAE: Neosarmatium meinerti (De Man, 1887) [previous Australian records of this species described as a separate species, Neosarmaium australiense Ragioneri, Fratini & Schubart, 2012] — Ragionieri, L., Fratini, S. & Schubart, C.D. 2012. Revision of the Neosarmatium meinerti species complex (Decapoda: Brachyura: Sesarmidae), descriptions of three pseudocryptic Indo-West Pacific species. The Raffles Bulletin of Zoology 60(1): 71-87

Diagnosis

Carapace quadrate or quadrangular with lateral margins subparallel, divergent or convergent; regions often discernible, although grooves shallow; dorsal surface often with tufts of setae; body sometimes deeply vaulted; pterygostome, subbranchial and subhepatic regions covered in reticulated network of short, hooked, close-set setae, each usually having a small granule at its base. Anterolateral margins entire or with one or two (rarely several) epibranchial teeth, second often reduced to obtuse angle. Front broad, strongly deflexed. Orbits with lower border running obliquely downwards towards buccal cavern. Antennal flagellum slender, short; usually in orbital hiatus but sometimes excluded. Third maxillipeds leaving wide rhomboidal gap when closed; an oblique setose ridge running across merus and ischium; palp articulating at summit, or near antero-external angle of merus; exopod slender, flagellum more or less well developed, rarely absent. Chelipeds usually subequal, massive; chelae sometimes with stridulatory structures. Male abdomen may or may not completely cover sternum between last pair of legs.

General References

Davie, P.J.F. 1985. The biogeography of littoral crabs (Crustacea : Decapoda : Brachyura) associated with tidal wetlands in tropical and sub-tropical Australia. In, Bardsley, K.N., Davie, J.D.S. & Woodroffe, C.D. (eds). Coasts and Tidal Wetlands of the Australian Monsoon Region. Mangrove Monograph No. 1. Darwin : Australian National University North Australia Research Unit.

Davie, P.J.F. 1994. Variations in diversity of mangrove crabs in tropical Australia. Memoirs of the Queensland Museum 36(1): 55-58

Robertson, A.I. 1991. Plant-animal interactions and the structure and function of mangrove forest ecosystems. Australian Journal of Ecology 16: 433-443

Smith III, T.J., Boto, K.G., Frusher, S.D. & Giddins, R.I. 1991. Keystone species and mangrove forest dynamics: the influence of burrowing by crabs on soil nutrient status and forest productivity. Estuarine, Coastal and Shelf Science 33: 419-432

History of changes