Marine Biology Commons^™

What Is Known About Species Richness And Distribution On The Outer-Shelf South Texas Banks?, Harriet L. Nash, Sharon J. Furiness, John W. Tunnell Jr.

Gulf and Caribbean Research

The outer-shelf South Texas Banks, also known as the snapper banks, are known by fishermen to be excellent fishing grounds. However, few scientific studies have been conducted to describe the ecology of these uncommon but distinctive habitats. This paper describes results of a literature review and an assessment to determine what is known about the biota of the South Texas Banks and to assist in developing renewed interest and focus on these topographic highs. The outer-shelf South Texas Banks include relict coralgal reefs and relict barrier islands, and we also include data for a nearshore site, which is geographically and …

Marine Fungi Of U.S. Gulf Of Mexico Barrier Island Beaches: Biodiversity And Sampling Strategy, Allison Kathleen Walker

Dissertations

Marine fungi are an important but often overlooked component of marine ecosystems. Primarily saprotrophic, they are vital to coastal nutrient cycling processes and food webs. However, basic marine fungal distribution data are lacking in many parts of the world, as is knowledge of the sampling intensity required to characterize the biodiversity of these communities. The roles of substrate, season and latitude in shaping intertidal ascomycete community structure were examined for the U.S. Gulf of Mexico, and the role of sampling frequency on species richness estimates was also addressed. Best sampling practices were developed and 750 collections of beach detritus, sand …

Fluorescence And Size Characterization Of Dissolved Organic Matter In Riverine And Sea Waters In The Northern Gulf Of Mexico, Zhengzhen Zhou

Dissertations

Riverine export of dissolved organic matter (DOM) is an important component in marine carbon budget but the composition and phase partitioning are poorly quantified. Monthly water samples were collected from the lower Mississippi and Pearl rivers between January 2009 to August 2011 for DOM characterization using the fluorescence excitation emission matrix (FluoEEM) technique, coupled with parallel factor analysis (PARAFAC), and flow field-flow fractionation technique. DOM in the Pearl River showed higher dissolved organic carbon (DOC) concentration, temporal fluctuation, and aromaticity, reflecting instantaneous inputs of DOM from local soil and plant litter. In contrast, DOM in the Mississippi River exhibited lower …

Nutrient Depletion As A Proxy For Microbial Growth In Deepwater Horizon Subsurface Oil/Gas Plumes, Alan M. Shiller, Dongjoo Joung

Faculty Publications

The Deepwater Horizon accident resulted in a substantial uncontrolled hydrocarbon release to the northern Gulf of Mexico, much of which was entrained in deep submerged plumes. While bio-degradation of the hydrocarbons has been inferred from microbial biomass and genetics, the amount of conversion of oil and gas carbon to biomass remains uncertain having only been estimated in modeling studies. Here we examine correlated depletions of nitrate, phosphate and oxygen in the submerged plumes and conclude that a substantial portion of hydrocarbons in these plumes was converted to biomass (0.8-2 x 10(10) mol C). This contrasts with nutrient-limited surface waters where …

Effects Of Hypoxia And 4-Tert-Octylphenol On Gene Expression Profiles Of The Sheepshead Minnow (Cyprinodon Variegatus), Arthur Alan Karels

Dissertations

Hypoxia occurs in estuaries of northern Gulf of Mexico and world-wide, with increasing frequency/severity via eutrophication and anthropogenic influences. Hypoxia inducible factors (HIFs) form transcriptional complex and bind DNA at hypoxia responsive elements (HREs) in promoter regions of genes needed for systemic and cellular adaptation of fish to low dissolved oxygen (hypoxia, DO <2.0 mg/ml). Hypoxia-induced activation of HIF-αs can lead to a cascade of downstream activation, such as erythropoietin (EPO). Return to normal DO levels (normoxia), prolyl hydroxylases (PHDs) are activated to degrade HIF-αs back to baseline. Fish are affected by environmental estrogen mimics, like 4-tert-octylphenol (4tOP), binding estrogen receptor alpha (ERα) at estrogen responsive elements (EREs) and activating genes vitellogenin (VTG). Previous research showed overlap or crosstalk between these two mechanistic pathways. Hypoxia triggers unknown factors regulating ERE-mediated ERα signaling pathway, and stressor combinations could increase/decrease hypoxic or endocrine pathway. Research examined molecular/physiological effects of hypoxia (acute and chronic, moderate and severe) and 4tOP (~60μg/L)on adult male and/or female sheepshead minnow (Cyprinodon variegatus). Three genes identified, cloned, and sequenced (HIF-1α, HIF-2α, and PHD3), plus previously identified genes EPO and VTG, were examined in liver/testes exposed to hypoxia and/or 4tOP for cellular/physiological changes. Endpoints examined included mRNA expression from real-time PCR of HIF-1α, HIF-2α, PHD3, EPO, and VTG using cDNA from total RNA extracts, and microarray analyses of genes expressed during the transition from hypoxia back to normoxia. Phylogenetic analyses confirmed isolation of two HIF-α isofoms (HIF-1α and HIF-2α) and the PHD3 isoform. Significant up-regulation of PHD3 occurred within 10 hrs of chronic hypoxia, and persisted when severe (1.5 mg/L) and declined when moderate (~2.5mg/L). Significant up-regulation of HIF-1α and EPO occurred within 30 minutes to 2 hours of onset of acute severe and very severe (~1.08mg/L) hypoxia. Hypoxia acted similar to an estrogen mimic, with huge up-regulation of VTG gene expression in males, and increased VTG levels (additive effect) when hypoxia was combined with 4tOP. Microarray analyses showed 125 genes with significant transcriptional change, with up- or down-regulation from transitions of: (1) hypoxia (72 hrs) to normoxia (74 hrs) and (2) hypoxia+4tOP (72 hrs) to normoxia+4tOP (74 hrs).

Genetic Connectivity In Scleractinian Corals Across The Northern Gulf Of Mexico: Oil/Gas Platforms, And Relationship To The Flower Garden Banks, Daniel A. Brazeau, Paul W. Sammarco, James Sinclair

Pharmaceutical Sciences Faculty Publications

The 3,000 oil/gas structures currently deployed in the northern Gulf of Mexico (GOM) provide hard substratum for marine organisms in a region where such has been rare since the Holocene. The major exception to this are the Flower Garden Banks (FGB). Corals are known to have colonized oil/gas platforms around the FGB, facilitating biogeographic expansion. We ask the question, what are the patterns of genetic affinity in these coral populations. We sampled coral tissue from populations of two species occurring on oil and gas platforms: Madracis decactis (hermatype) and Tubastraea coccinea (invasive ahermatype). We sampled 28 platforms along four transects …

The Rise And Fall Of Crassostrea Virginica Oyster Reefs: The Role Of Disease And Fishing In Their Demise And A Vignette On Their Management, Eric N. Powell, John M. Klinck, Kathryn Ashton-Alcox, Eileen E. Hofmann, Jason Morson

CCPO Publications

We describe a model designed to simulate the shell carbonate budget of an oyster reef.We identify five parameters descriptive of basic characteristics of the shell carbonate budget of a reef that limit simulation accuracy. Two describe the TAZ (taphonomically-active zone) and the distribution of shell carbonate within it. One is the taphonomic rate in the TAZ. Two determine the volume contribution of shell carbonate and the taphonomic loss rate within the reef framework. For Mid-Atlantic estuaries, model simulations suggest that reef accretion only occurs if oyster abundance is near carrying capacity. Simulations further suggest that reef accretion is infeasible for …

Environmental Influences On Juvenile Fish Abundances In A River-Dominated Coastal System, Laure Carassou, Brian Dzwonkowski, Frank J. Hernandez, Jr., Sean P. Powers, William M. Graham, Kyeong Park, John Mareska

University Faculty and Staff Publications

We investigated the influence of climatic and environmental factors on variations in juvenile abundances of marine fishes in a river-dominated coastal system of the north-central Gulf of Mexico, where an elevated primary productivity sustains fisheries of high economic importance. Fish were collected monthly with an otter trawl at three stations near Mobile Bay from 1982 to 2007. Fish sizes were used to isolate juvenile stages within the data set, and monthly patterns in juvenile fish abundance and size were then used to identify seasonal peaks for each species. The average numbers of juvenile fish collected during these seasonal peaks in …

Thermal Tolerance Of Age-0 Gulf Of Mexico Striped Bass (Morone Saxatilis): Ontogenetic And Genetic Effects, Corey Robert Anderson

Master's Theses

Striped bass, Morone saxatilis, were historically abundant in the Gulf of Mexico region but were largely extirpated from most Gulf rivers by the early 1960s. Since 1967 hatchery stocking has supported populations in Mississippi rivers and to date there is no evidence of natural reproduction. Intolerance of striped bass to high water temperature is a potential factor negatively impacting Gulf striped bass survival and reproductive fitness, and may be a limiting factor to reintroduction of the species in Mississippi. This work contributed to restoration efforts by establishing molecular tools necessary for genetic monitoring of striped bass restoration, and evaluating …

A 50 Year Accomplishment In Marine Science: A History Of The Journal Published By The Gulf Coast Research Laboratory, Mark S. Peterson, Nancy J. Brown-Peterson, Sara E. Lecroy, Joyce M. Shaw, James S. Franks, Richard W. Heard

Gulf and Caribbean Research

The Gulf Coast Research Laboratory (GCRL) has a 50 year history of annual publication of the peer-reviewed journal Gulf and Caribbean Research (GCR, 2000-present; formerly Gulf Research Reports (GRR) from 1961—1999). Other extant journals serving the region during this time include Contributions in Marine Science (since 1945), Proceedings of the Gulf and Caribbean Fisheries Institute (since 1948), Bulletin of Marine Science (since 1951), Revista de Biología Tropical (since 1953), and Caribbean Journal of Science (since 1961). In the early years of the GCR publication, papers were primarily concerned with research in Mississippi and the northern Gulf of Mexico (GOM), and …

Deglacial Abrupt Climate Change In The Atlantic Warm Pool: A Gulf Of Mexico Perspective, Carlie Williams, Benjamin P. Flower, David W. Hastings, Thomas P. Guilderson, Kelly A. Quinn, Ethan A. Goddard

Marine Science Faculty Publications

During the last deglaciation, Greenland ice core and North Atlantic sediment records exhibit multiple abrupt climate events including the Younger Dryas cold episode (12.9-11.7 ka). However, evidence for the presence of the Younger Dryas in the Gulf of Mexico (GOM) and the relationship between GOM sea surface temperature (SST) and high-latitude climate change is less clear. We present new Mg/Ca-SST records from two varieties of the planktonic foraminifer Globigerinoides ruber (white and pink) to assess northern GOM SST history from approximately 18.4-10.8 ka. Thirty-five accelerator mass spectrometry (AMS) C-14 dates from Orca Basin core MD02-2550 provide excellent age control and …

Distributions Of Sharks Across A Continental Shelf In The Northern Gulf Of Mexico, J. Marcus Drymon, Sean P. Powers, John Dindo, Brian Dzwonkowski, Terry A. Henwood

University Faculty and Staff Publications

Declines in shark populations have sparked researchers and fishery managers to investigate more prudent approaches to the conservation of these fish. As managers strive to improve data collection for stock assessment, fisheries-independent surveys have expanded to include data-deficient areas such as coastal regions. To that end, a catch series from a nearshore survey off Alabama was combined with data from a concurrent offshore survey with identical methodology to examine the depth use of sharks across the continental shelf (2–366 m). The combined data set contained 22 species of sharks collected from 1995 to 2008: 21 species in the offshore data …

Life History And Habitat Use Of The Juvenile Alabama Shad (Alosa Alabamae) In Northern Gulf Of Mexico Rivers, Paul Fraser Mickle

Dissertations

The Alabama shad, Alosa alabamae, is an anadromous species that is in decline and has seen extirpations from impoundments as well as decreased water quality. Alabama shad live in the Gulf of Mexico and ascend Northern Gulf of Mexico Drainages to reproduce early in the year (January-May). The juveniles spend the majority of the year in these freshwater systems before emigrating out to the Gulf of Mexico as late as December.

This dissertation focuses on the juvenile life stages that occur within the Northern Gulf of Mexico drainages. Spawning conditions of the river, as well as the habitat and diet, …

Endohelminths Of A Snake Mackerel, Gempylus Serpens (Trichiuroidea: Gempylidae), From The Gulf Of Mexico, Charles K. Blend, Norman O. Dronen, James S. Franks, George W. Benz

Gulf and Caribbean Research

Endohelminths are reported from a female snake mackerel, Gempylus serpens (Trichiuroidea: Gempylidae), captured from a depth of 61 m in the Gulf of Mexico 140 km south of the mouth of Mobile Bay, AL, in August 1998. A diverse endohelminth parasite fauna was found: 29 plerocercoid type I tetraphyllideans from the lower intestine; 4 didymozoid metacercariae allocated to the collective group Monilicaecum and one didymozoid metacercaria of the collective group Torticaecum from the pyloric cecum; one juvenile Gonocerca phycidis from the stomach; and 5 larvae (L3 stage) comprising 3 species of Anisakis from the pyloric cecum. These nematodes were identified …

Recruitment And Colonization Of Macroalgae To A Newly Constructed Rocky Intertidal Habitat In The Northwest Gulf Of Mexico, Ryan L. Fikes, Roy L. Lehman

Gulf and Caribbean Research

Marine macroalgal assemblages on artificial structures play an important ecological role in coastal and estuarine ecosystems and may supplement natural communities in nearby waters. The rocky jetties of Packery Channel, located near Corpus Christi, Texas represent a recent addition of hard structure for colonization in the northwest Gulf of Mexico. The purpose of this research was to monitor the initial immigration of macroalgal species during the first year of colonization and determine the effects of wave energy on recruitment. Ten sampling sites were established along the offshore portion of the new Packery Channel jetties. Samples were taken bimonthly from along …

Factors Influencing The Environmental Quality Of The Bay Of Saint Louis, Mississippi And Implications For Evolving Coastal Management Policies, Pradnya Ankush Sawant

Dissertations

The Bay of St. Louis, MS is a small northern Gulf of Mexico estuary that has been identified by the Mississippi Department of Environmental Quality (MDEQ) as an impaired waterbody for its designated uses, mainly due to the presence of pollutant pathogens. A systematic study of this estuary was important to understand the behavior and responses of the bay to several natural and anthropogenic forcing factors. A 14- month long study (bimonthly sampling) to evaluate its environmental quality was undertaken from April 2003 to May 2004. Environmental quality was defined as "the health of an ecosystem characterized in terms of …

First Record Of Ceratapsis Monstrosa, A Larval Oceanic Penaeoid Crustacean, From The Gulf Of Mexico, James S. Franks, Adrienne Russell Flowers

Gulf and Caribbean Research

The genus Cerataspis (Gray, 1838) (Crustacea, Decapoda), assigned to the Penaeoidea by Burkenroad (1936) and Heegaard (1966), has circumglobal distribution between 40ºN and 40ºS (Morgan et al. 1985) and is represented in the Atlantic Ocean by two rarely collected species, C. monstrosa and C. petiti. Descriptions of both species are based on the larval forms since their adult form remain undescribed (Morgan et al. 1985). Although the larval development of Cerataspis is described by five mysis stages (I-V) (Heegaard 1966), the large larva is very un-mysid like and appears more like that of a megalops with the abdomen bend …

Relative Abundance Of Pelagic Sharks In The Western North Atlantic Ocean, Including The Gulf Of Mexico And Caribbean Sea, Enric Cortes, Craig A. Brown, Lawrence R. Beerkircher

Gulf and Caribbean Research

Little information exists on the status of pelagic shark populations in the Atlantic Ocean, especially in the Gulf of Mexico and Caribbean Sea. We derived indices of relative abundance for pelagic sharks based on mandatory logbooks and observer reports from a scientific observer program of the United States (US) pelagic longline fleet. Time series data from the pelagic longline logbook program (1986-2005) and the pelagic longline observer program (1992-2005) were standardized with Generalized Linear Model (GLM) procedures. Declines in relative abundance for the 6 pelagic shark species or genera examined in the logbook data analysis ranged from 43% for mako …

Management In The Gulf And Caribbean: Mosaic Or Melting Pot?, Patrick Mcconney, Hazel A. Oxenford, Milton Haughton

Gulf and Caribbean Research

Does ''managing large pelagic fishes" mean the same thing across the diversity of maritime jurisdictions, governance arrangements, economies, languages, cultures, scales of operation and other features of the Gulf and Caribbean region? It would be surprising if it did. Yet international fisheries management urges this mosaic of management to become a melting pot; at least integrated, even if differentiated. This paper examines some themes underlying whether a mosaic or melting pot is the most apt metaphor for where we are, and are headed, in attempts to manage large pelagic fishes in the region. We pay particular attention to the multi-dimensional …

Large Pelagic Fishes In The Caribbean Sea And The Gulf Of Mexico: Current Status And Integrated Management, Mark S. Peterson, Nancy J. Brown-Peterson, James S. Franks

Gulf and Caribbean Research

A symposium convened on 7 November 2006 in conjunction with the 59th annual meeting of the Gulf and Caribbean Fisheries Institute in Belize City, Belize.

Distribution Of Molidae In The Northern Gulf Of Mexico, Gregory L. Fulling, Dagmar Fertl, Kevin Knight, Wayne Hoggard

Gulf and Caribbean Research

We compiled all available sighting, stranding and bycatch data for the Family Molidae (molas) in the northern Gulf of Mexico (NGOM) to assess spatial and temporal distribution. Overall, 483 records were collected from shipboard and aerial surveys, fisheries bycatch, and strandings. Molas were recorded year-round, with a ubiquitous distribution in both nearshore and offshore waters. Ocean sunfish (Mola mola) were sighted with greatest frequency during the winter (December thru April) in sea surface temperature < 24° C. Potential reasons for increased sightings during winter may be related to the lack of a well-defined thermocline in the NGOM; the species' "basking" behavior associated with thermoregulation; and oxygen replenishment after long, deep dives to oxygen-deficient depths.

Patterns Of Vertical Habitat Use By Atlantic Blue Marlin (Makaira Nigricans) In The Gulf Of Mexico, Richard T. Kraus, Jay R. Rooker

Gulf and Caribbean Research

We examined data from pop-up archival transmitting (PAT) tags (n = 18) to characterize aspects of vertical habitat use by blue marlin (Makaira nigricans) from the Gulf of Mexico (GOM). Two of these tags were recovered and provided fine-scale information about diving patterns and the relationship between time at depth and temperature. Similar to previous studies, blue marlin in the GOM spent most of their time at the surface and at temperatures within 3° C of surface temperatures. Time at depth was multimodal and the magnitude of the smaller modes was dependent upon the strength and depth …

Marionia Tedi Ev. Marcus, 1983 (Nudibranchia, Tritoniidae) In The Gulf Of Mexico: First Record Of An Opisthobranch Mollusk From Hydrocarbon Cold Seeps, Angel Valdes

Gulf and Caribbean Research

Cold seeps in the Gulf of Mexico contain relatively diverse molluscan assemblages primarily composed of species that support chemoautotrophic symbionts, such as vesicomyid and mytilid bivalves, but also numerous species of shelled gastropods, bivalves, monoplacophorans, and polyplacophorans (Cordes 2004).

Recent exploration of hydrocarbon seep sites in the Mississippi Canyon and the Vioska Knoll revealed the presence of an unidentified species of nudibranch. The present paper describes the single specimen collected, which constitutes the first published record of an opisthobranch mollusk from a cold seep. The material examined is deposited at the Field Museum of Natural History (FMNH).

Nitrogen Fixation And Release Of Fixed Nitrogen By Trichodesmium Spp. In The Gulf Of Mexico, Margaret R. Mulholland, Peter W. Bernhardt, Cynthia A. Heil, Deborah A. Bronk, Judith M. O'Neil

OES Faculty Publications

During a 3-yr study in the Gulf of Mexico, we measured dinitrogen (N₂) fixation and nitrogen (N) release by Trichodesmium and compared these rates with water column N demand and the estimated N necessary to support blooms of Karenia brevis, a toxic dinoflagellate that severely affects the West Florida shelf. Net and gross N₂ fixation rates were compared in simultaneous incubations using ¹⁵N₂ uptake and acetylene reduction, respectively. The difference between net and gross N₂ fixation is assumed to be an approximation of the rate of N release. Results demonstrate that Trichodesmium in …

High Cyanobacterial Abundance In Three Northeastern Gulf Of Mexico Estuaries, Michael C. Murrell, Jane M. Caffrey

Gulf and Caribbean Research

Aquatic phytoplankton comprise a wide variety of taxa spanning more than 2 orders of magnitude in size, yet studies of estuarine phytoplankton often overlook the picoplankton, particularly chroococcoid cyanobacteria (cf. Synechococcus). Three Gulf of Mexico estuaries (Apalachicola Bay, FL; Pensacola Bay, FL; Weeks Bay, AL) were sampled during summer and fall 2001 to quantify cyanobacterial abundance, to examine how cyanobacterial abundance varied with hydrographic and nutrient distributions, and to estimate the contribution of cyanobacteria to the bulk phytoplankton community. Cyanobacterial abundances in all 3 estuaries were high, averaging 0.59 ± 0.76 X 10⁹ L^–1 in Apalachicola Bay, …

Manatee Occurrence In The Northern Gulf Of Mexico, West Of Florida, D. Fertl, A.J. Schiro, G.T. Regan, C.A. Beck, N. Adimey, L. Price-May, A. Amos, G.A.J. Worthy, R. Crossland

Gulf and Caribbean Research

Reports of West Indian manatees (Trichechus manatus) in the US Gulf of Mexico west of Florida have increased during the last decade. We reviewed all available manatee sighting, capture, and carcass records (n = 377) from Alabama, Louisiana, Mississippi, and Texas since the early 1900s; only 40 of these were previously published. Manatees were reported most often in estuarine habitats, usually either near a freshwater source or natural or industrial warm-water springs/runoffs during winter months. The recent increase in manatee records may be due to a combination of increased public awareness and dispersal of manatees, most likely seasonal …

Stomatopoda (Crustacea: Hoplocarida) From The Shallow, Inshore Waters Of The Northern Gulf Of Mexico (Apalachicola River, Florida To Port Aransas, Texas), John M. Foster, Brent P. Thoma, Richard W. Heard

Gulf and Caribbean Research

Six species representing the order Stomatopoda are reported from the shallow, inshore waters (passes, bays, and estuaries) of the northern Gulf of Mexico limited to a depth of 10 m or less, and by the Apalachicola River (Florida) in the east and Port Aransas (Texas) in the west. With the exception of the “live bottom” gonodactylid, Neogonodactylus bredini (Manning), these predatory crustaceans usually inhabit burrows in mud, sand-mud, and sand substrata in coastal and shelf waters. The species treated in this paper are Neogonodactylus bredini (Manning), Lysiosquilla scabricauda (Lamarck), Bigelowina biminiensis (Bigelow), Coronis scolopendra Latreille, Squilla empusa Say, and Gibbesia …

Millennial- To Century-Scale Variability In Gulf Of Mexico Holocene Climate Records, R. Z. Poore, H. J. Dowsett, S. Verardo, Terrence M. Quinn

Marine Science Faculty Publications

Proxy records from two piston cores in the Gulf of Mexico (GOM) provide a detailed (50–100 year resolution) record of climate variability over the last 14,000 years. Long‐term (millennial‐scale) trends and changes are related to the transition from glacial to interglacial conditions and movement of the average position of the Intertropical Convergence Zone (ITCZ) related to orbital forcing. The δ¹⁸O of the surface‐dwelling planktic foraminifer Globigerinoides ruber show negative excursions between 14 and 10.2 ka (radiocarbon years) that reflect influx of meltwater into the western GOM during melting of the Laurentide Ice Sheet. The relative abundance of the …

Chlorophyll Dispersal By Eddy-Eddy Interactions In The Gulf Of Mexico, M. Toner, A. D. Kirwan, A. C. Poje, L. H. Kantha, Frank E. Muller-Karger, C. K. R. T. Jones

Marine Science Faculty Publications

A Lagrangian analysis of the transport and dispersal of plumes observed in satellite‐derived ocean color images was conducted using a data‐assimilating model of the Gulf of Mexico. The interaction between pervasive cyclonic and anticyclonic eddies in the Gulf generated advective paths that connect remote shelf regions. These paths aligned remarkably well with the plume events recorded with the chlorophyll‐a ocean color product from SeaWiFS. Two such events were studied. In one event material was transported in a thin strip between the northern wall of the Loop Current and an adjacent cyclone, connecting the eastern Campheche shelf (off the Yucatan Peninsula) …

Tanaidacea (Crustacea: Peracardia) Of The Gulf Of Mexico. X. The Question Of Being Male, Kim Larsen

Gulf and Caribbean Research

Three new species Parafilitanais mexicana, Collettea elongata, and Paragathotanais medius are described from deep-sea localities in the Gulf of Mexico. The male of Parafilitanais does not vary conspicuously from the female, except for possessing pleopods. Male Paragathotanais reveal that the mouthparts display some degree of sexual dimorphism. Males of all 3 species possess functional mouthparts. The problems identifying male Tanaidacea are discussed. The number of terminal spiniform setae on the maxillule is considered invalid as a diagnostic character. Keys to the species of Parafilitanais and Paragathotanais are given.