POLYCHAETOUS ANNELIDS OF THE GULF OF MEXICO 



By Olga Hartman,' Allan Hancock Foundation, University of Southern California 



For the purpose of this article the area of the 

 Gulf of Mexico is limited to the approximately 

 ellipse-shaped enclosure that terminates at its 

 eastern end in Cape Sable, southern Florida, and 

 at its other extremity in Cabo Catoche, northern 

 Yucatan Province, Mexico. I exclude the north- 

 western end of Cuba and the Florida Keys, both 

 of which fringe the Gulf of Mexico at the far 

 eastern end, since in their polychaete fauna these 

 areas may be regarded as part of the West Indian 

 zoogeographic region and thus differ from that of 

 most of the Gulf of Mexico. 



The physical features of the area under consid- 

 eration favor the development of an invertebrate 

 fauna dominant in sand and mud dwelling species. 

 Such are the habitats of many groups of marine 

 annelids which may be expected to occur in 

 prodigious numbers but which have still remained 

 largely unknown. Based on records in the writer's 

 possession, it can now be stated that there is a 

 large endemic population; this may have had its 

 origin within the enclosure of the Gulf and pos- 

 sibly in its center or western half. Thus, there 

 are unique genera, a surprising number of unde- 

 scribed species and subspecies. Some of them 

 show marked affinities with the amielids of eastern 

 United States, particularly in its southern end; 

 others are akin with those of the Gulf of Califor- 

 nia and southern California. Still others have af- 

 finities with those of Brazil and less so with those 

 of New England. Some species may be regarded 

 as circummundane or be widely dispersed, thus 

 common also to the Mediterranean Sea and west- 

 ern Europe. The annelids of westena Florida are 

 clearly related to those of the West Indies except 

 for those species which may have been swept 

 eastward from the western half of the Gulf. The 

 floating logs, weeds, and other pelagic or drifting 

 objects support an anneUd fauna like that of the 



West Indies. The sponge, ascidian, and oyster- 

 clump fauna appears to be similar throughout the 

 Gulf. 



The number of species which can be recorded 

 from the literature is disappointingly small (less 

 than 60). This number can be easily tripled when 

 the records now in the writer's collections are 

 published.^ The records given below are based on 

 species associated with a wide variety of habitats 

 and only in a limited extent those from sand 

 or mud flats. The last, however, should yield the 

 richest fauna when the Gulf of Mexico will be more 

 completely known. 



The polychaetous annelids are summarized by 

 family. The arabic number (1 to 59) preceding 

 the name is consecutive. An asterisk preceding 

 the name indicates that a change is newly made 

 herein. The date following the original author's 

 name is that of the erection of the species. The 

 literature citations are listed at the end. A 

 short appendix at the end summarizes ecological 

 associations insofar as they are recorded. 



Family POLYNOIDAE 



*1. Lepidatnetria commensalis Webster, 1879. 



As Lepidaslheiiia laclea Treadwell, 1939, pp. 3-4, 

 figs. 13-15, from Galveston, Texas. Commensal in tubes 

 of terebellid worms or free-living. Elsewhere known from 

 eastern United States. The synonymy is here newly 

 indicated. 

 *2. Lepidonotus sublevis Verrill, 1893. 



As Lepidonotus pallidus Treadwell, 1939, p. 3, figs. 10-12, 

 from Freeport, Texas, and as Lepidonotus squamatus 

 Warren, 1942, p. 45, from Grand Isle, Louisiana. Occurs 

 in crevices, in oyster clumps, in ascidian masses. Else- 

 where known from eastern United States. The two 

 synonymies are here newly indicated. 

 3. Lepidonotus variabilis Webster, 1879. 



Reported by Warren, 1942, p. 45, from Grand Isle, 

 Louisiana, and by Hartman, 1945, p. 10, from south- 



' Contribution No. 120, from tlie Allan Hancock Foundation. 



! See Hartman, O., 1951, Thi' Littoral Marine Annelids of the Oulf o' 

 Mexico, in Pub. of the Institute of Marine Science 2 (1): 7-124, published 

 since the preparation of this article. 



413 



