Family NEBALIIDAE Samouelle, 1819

Museums

Regional Maps

• Nebaliidae Samouelle, G. 1819. The Entomologist's Useful Compendium; or an introduction to the knowledge of British Insects, comprising the best means of obtaining and preserving them, and a description of the apparatus generally used; together with the genera of Linné, and modern methods of arranging the Classes Crustacea, Myriapoda, spiders, mites and insects, from the affinities and structure, according to the views of Dr. Leach. Also an explanation of the terms used in entomology; a calendar of the times of appearance and usual situations of near 3,000 species of British Insects; with instructions for collecting and fitting up objects for the microscope. London : Thomas Boys 496 pp. 12 pls. [100].

  Type genus:

   Nebalia Leach, 1814 [by monotypy].

Introduction

Nebaliids are typically small, marine, benthic, filter-feeding crustaceans that seem to prefer soft mud or muddy sand substrates that are low in oxygen. They are found from shallow nearshore waters into abyssal depths. Most species have been described from the Atlantic, but there appears to have been a paucity of critical taxonomic investigation of the Indo-Pacific fauna, with species often being ascribed too quickly to Atlantic forms. Thus, there may be considerably higher diversity than apparent from present records (see Dahl 1990; Walker-Smith 1998). Walker-Smith & Poore (2001) have split off Paranebalia and Levinebalia to form a new family Paranebaliidae. Thus two of the five remaining genera of Nebaliidae are now recorded from Australia. Martin et al. (1996) and Walker-Smith & Poore (2001) provided keys to genera.

Diagnosis

Subterminal rostral spine rarely present; keel sometimes present. Visual elements present or absent. Supra-ocular scale sometimes present. Antenna 1, anterodenticulate fourth article absent; male, flagellum not swollen, but may have numerous aesthetascs. Antenna 2, peduncle without cuticular outgrowths or minute denticles; articles 3 and 4 sometimes fused; male antenna 2 greatly elongate, reaching to the caudal furca (unknown for Dahlella). Mandible incisor, present (except for Speonebalia). Molar process well developed, without setal brush; without accessory process; sometimes with accessory tooth/spine. Maxilla 1 palp long, well developed. Maxilla 2 with at least first three endites well developed; much smaller than thoracopod 1. Thoracopods not extending well beyond ventral margin of carapace; closely spaced. Thoracopod 1 differing only slightly from thoracopods 2–7. Thoracopods 2–5 epipod longer than exopod, or absent; endopods showing a degree of articulation. Pleonites 4–7 crenate over entire margin. Pleopod 1 exopod generally with comb-row. Pleopod 2–4 exopod with parallel margins or slightly expanded medially; outer margins with setae sometimes in pairs. Pleopod 5 longer or shorter than pleopod 6. Pleopod 6 uni- or biarticulate. Caudal rami tapering evenly to tip. Thorax not inflated, body cuticle firm. Carapace strongly emarginate mid-sagittally. Entire body length less than 20 mm. (After Walker-Smith & Poore 2001)

General References

Dahl, E. 1990. Records of Nebalia (Crustacea Leptostraca) from the Southern Hemisphere — a critical review. Bulletin of the British Museum (Natural History) Zoology 56(1): 73-91

Martin, J.W., Vetter, E.W. & Cash-Clark, C.E. 1996. Description, external morphology, and natural history observations of Nebalia hessleri, new species (Phyllocarida: Leptostraca), from southern California, with a key to the extant families and genera of the Leptrostraca. Journal of Crustacean Biology 16(2): 347-372

Walker-Smith, G. & Poore, G.C.B. 2001. A phylogeny of the Leptostraca (Crustacea) with keys to families and genera. Memoirs of Museum Victoria 58(2): 383-410

Walker-Smith, G.K. 1998. A review of Nebaliella (Crustacea: Leptostraca) with the description of a new species from the continental slope of southeastern Australia. Memoirs of Museum Victoria 57(1): 39-56

History of changes