NOTES ON THE CHAETOGNATHA OF THE GULF OF MEXICO 



By E. Lowe Pierce, Department of Biology, University of Florida 



The chaetognaths are elongate, transparent, Dr. H. B. Moore of the Marine Laboratory, 



marine animals. They range in length, when University of Miami. The data and the list of 



matm-e, from one-half to several centimeters. One species for each sample aie given below: 

 or two pairs of lateral fins and a caudal fin are First sample: Atlantis. Location: 27°15' N., 



present. A group of hooks, or seizing jaws, are 90°09' W. Date: January 18, 1947. Depth of 



arranged on either side of the head by means of tow: 495-749 meters, 

 which they catch their prey. The body is divided species Relative abundance 



into head, trunk, and tail regions. They are S. bipunctata Quoy a,nd Ga,ima.Td Common. 



hermaphroditic with the ovaries in the trunk and S. enflata Grassi Common. 



the testes m the taU segment. ^- ^erratod^ntata Krohn Common. 



„ /•.! • 1- .• , • f . ^11, S. hexaptera dUTbigny bcarce. 



Because of their distmctive features the arrow- ^ ^^^^ j-^.^^^ g^^^^^ 



worms" are usually set apart from the other worms g. macrocephala Fowler Scarce. 



into a separate phylum. At present about 9 E ukrohnia hamata {Mobms) Common. 



genera and 38 species are recognized. The genus PterosagMa draco (Krohn) Scarce. 



Sagitta is by far the largest both in number of Krohniita subiilis (Grassi) Scarce. 



species and in number of individuals. Second sample: Atlantis. Location: 26°24' N., 



Few published records exist concerning chaetog- 87°15' W. Date: 1947. 

 naths in the Gulf of Mexico. Ritter-Zahony Note: No further data available from sample. 



(1910) described specimens taken from the region speau Relative abundance 



of the Dry Tortugas, Florida. Conant (1895, S.hipundaia Common 



1896) published records of specimens from the ^.'^^^^ala::///:"^//":/:^://^/^^/- Commo": 



West Indies and Beaufort, North Carolina. Davis g hexaptera Common. 



(1949) and King (1949) briefly mentioned chae- s. macrocephala Scarce. 



tognaths in their studies of plankton of the Gulf Pterosagitta draco Common. 



coast of Florida. Inasmuch as many of the species Krohnitia subtilis Common. 



in the Gulf have a wide and in some instances an A comparison of the chaetognaths taken from 



almost cosmopolitan distribution in the warm the Gulf coast of Florida and the above two 



oceanic waters, many references to such species samples from the offshore waters in the Gulf 



collected in other bodies of water may be found reveals an almost totally different fauna. In 



in the literature. fact, out of a total of 14 species only 1 (S. enflata) 



A recent study (Pierce 1951) of the Chaetog- was common to both inshore and offshore waters, 



natha of the Gulf coast of Florida revealed two It would be well to keep in mind, however, that 



genera and five species present in the inshore the depth at which the samples were collected 



waters These are: Sagitta hispida Conant, Sagitta was quite different for the first Atlantis sample, 



helenae Ritter-Zahony, Sagitta tenuis Conant, and probably for the second as well, from that 



Sagitta enflata Grassi, and Krohnitta paciflca of the coastal samples where the water was never 



(Aida). over 20 meters deep. This difference in collecting 



Two samples collected by the Atlantis from the depth between the two areas would undoubtedly 



offshore waters of the northern portion of the accentuate the faunal differences; however, the 



Gulf of Mexico were obtained through the courtesy appearance of only one species in common is 



of the Woods Hole Oceanographic Institution and certainly noteworthy. 



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