A study of the benthic macroinvertebrates of the continental shelf of the northern Gulf of Mexico

Abstract

The present study details the occurrence and distribution of the macroninvertebrates of the continental shelf of much of the Gulf of Mexico. The primary study area is the northern Gulf, between Corpus Christi, Texas, and Pensacola, Florida; some information is also provided on the fauna of the Mexican coast, between the mouth of the Rio Soto la Marina, Tamaulipas, and Progreso, Yucatan. The study is based on collections from 146 trawl samples, mostly collected in the depth range of 18 to 183 m. Approximately 50,000 specimens were collected and processed. These represent 356 species in 261 genera and 161 families, and include sponges (10 species), coelenterates (41 species), worms (26 species, in 5 phyla), molluscs (116 species), arthropods (113 species), echinoderms (30 species), ectoprocts (9 species), and urochordates (11 species). Essentially all species are synoptically described, with pertinent comments on distribution and natural history, and are photographically illustrated. Literature pertaining to the fauna and physical characteristics of the Gulf of Mexico is reviewed and discussed. Based upon the results of the present study, then published literature, and unpublished reports, twelve faunal assemblages characteristic of the northern Gulf, from Brownsville, Texas, to Tampa Bay, Florida, in the depth range of 4 to 200 m are proposed. These assemblages are: (a) inner shelf assemblage, Texas-Louisiana shelf (4-20 m); (b) pro-delta fan assemblage (4-20 m); (c) pro-delta sound assemblage (4-20 m); (d) inner shelf assemblage, West Florida shelf (4-20 m); € intermediate shelf assemblage, Texas-Louisiana shelf (20-60 m); (f) intermediate shelf assemblage, West Florida shelf (20-60 m); (g) outer shelf assemblage, Texas-Louisiana shelf (60-120 m); (h) outer shelf assemblage, West Florida shelf (60-120 m); (i) upper slope assemblage, Texas-Louisiana shelf (120-200 ,); (j) upper slope assemblage, West Florida shelf (120-200 m); (k) submarine bank assemblage, Texas-Louisiana shelf (20-100 m); and (l) Florida Middle Ground assemblage, (30-60 m). Physical characteristics, geographic extent, and fauna characteristic of each assemblage are briefly described.