Six New Species of Free-Living Marine Nematodes (Nematoda: Araeolaimida: Enoplida) from Two Estuaries in Northwest Florida, U.S.A.

Abstract

Five new species of free-living marine nematodes in the order Araeolaimida and one new species in the order Enoplida are described from non-vegetated subtidal and beach sediments in St. Andrew Bay and Lake Powell, Bay County, Florida, U.S.A. Plectolaimus supplementus n. sp. differs from the similar Plectolaimus magdalenae in the presence of tooth-like structures in the esophagus, longer spicules, and a greater number of pre-anal supplements. The males of Paraphanolaimus bayensis n. sp. differ from all other males in the genus in the shape of the gubernaculum and in the presence of numerous large cup-shaped pre-anal supplements as well as tubular supplements. Females of P. bayensis n. sp. can be differentiated from the other females in the genus by the presence of midventral pores. Odontophora brevispicula n. sp. differs from the only other member of the genus having short straight spicules (Odontophora mercurialis) in the shape of the spicules and gubernaculum. The males of Odontophora carrolli n. sp. and 0. articulata n. sp. differ from the males of other members of the genus in the presence of large and distinct pre-anal supplements. They differ from one another in the shape of the pre-anal supplements and in the shape of the gubernaculum. Bathylaimus longicorpus n. sp. differs from the other members of the genus having teeth in the stoma in the number and arrangement of the teeth. Free-living marine nematodes were collected from various sites in two estuaries in Bay County, Florida from 1981 to 1986; these sites were located in St. Andrew Bay and Lake Powell. St. Andrew Bay is part of a larger estuarine system on the north coast of the Gulf of Mexico. The system is open to the Gulf through two passes. Lake Powell is a small estuary just west of the St. Andrew Bay system. It is connected to the Gulf of Mexico by a narrow, shallow, meandering inlet that periodically closes and isolates the lake from the Gulf of Mexico. Collection sites in both estuaries were located in non-vegetated subtidal areas and non-vegetated sites immediately above mean high tide level. Sediments at the sites consisted of fine to medium sand with varying degrees of silt and organic material. MATERIALS AND METHODS Sediment samples were obtained with a 9-cm diameter core sampler to a depth of 4-10 cm, depending on the site. Nematodes were extracted by repeated washing of the sediment in water from the site, allowing the heavier particles to settle for 15 sec and decanting the supernatant water and suspended material 1I thank Dr. W. Duane Hope for his review of the manuscript, examination of the specimens, and for his many helpful comments and suggestions. I thank also Dr. Armen C. Tarjan for his review of the manuscript and his continuing encouragement. Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. TRANS. AM. MICROSC. Soc., 107(1): 79-95. 1988. ? Copyright, 1988, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.249 on Wed, 03 Aug 2016 06:04:11 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. to a second container. The suspended material from four washings was allowed to settle for 15-20 min and the supernatant water was decanted. Nematodes were removed alive from the remaining sediment, fixed in hot 4% formalin in seawater or hot alcohol-formalin-acetic acid for 24 h, cleared in glycerine, and mounted in anhydrous glycerine. Measurements were made with a calibrated ocular micrometer. All measurements are given in Aum unless otherwise stated, and the mean is followed by the range in parentheses. Spicular lengths are given as the chord of the spicular arc. The taxonomic heirarchy followed is that of Gerlach & Riemann (1974).