Selachohemecus benzi n. sp. (Digenea: Sanguinicolidae) from the blacktip shark Carcharhinus limbatus (Carcharhinidae) in the northern Gulf of Mexico

Selachohemecus benzi Bullard & Overstreet n. sp. infects the heart and kidney of the blacktip shark Carcharhinus limbatus in the northern Gulf of Mexico off Florida and Mississippi, USA. Specimens of S. olsoni Short, 1954, the only congener and only other named blood fluke reported from a chondrichthyan in the Gulf of Mexico, were collected from the heart of the Atlantic sharpnose shark Rhizoprionodon terraenovae from two new localities, Apalachicola Bay, Florida, and Mississippi Sound, Mississippi, USA. The new species differs from S. olsoni by having a larger body (1.4-3.8 mm long), robust tegumental body spines numbering 51-63 along each lateral body margin, a testis extending from the posterior caeca to the ovary, and a medial ovary with lobes. We amend the diagnosis of Selachohemecus Short, 1954 to accommodate it and provide a diagnostic key for all named chondrichthyan blood flukes.     

Overstreetia olsoni n. sp. (Digenea: Zoogonidae) from the Capricorn silverside Atherinomorus capricornensis (Woodland) (Atherinidae) off Heron Island, southern Great Barrier Reef

A new species, Overstreetia olsoni, is described from Atherinomorus capricornensis off Heron Island on the Great Barrier Reef off Queensland, Australia. It differs from its only known congener in that the enlarged spines of the circum-oral rows are smaller ( ≤ 4.5 × 3.5 vs ≤ 21.5 × 10.5μm), the sucker-ratio is smaller (1: 0.97–1.01 vs 1:1.8) and the eggs are larger (40–45 × 22–28 vs 34–37 × 17–22μm).     

First record of dicephalia in a bull shark Carcharhinus leucas (Chondrichthyes: Carcharhinidae) foetus from the Gulf of Mexico,U.S.A.

The first recorded incidence of dicephalia in a bull shark Carcharhinus leucas is reported from a foetus collected by a fisherman in the Gulf of Mexico near Florida, U.S.A. External examination, Radiography and magnetic resonance imaging revealed a case of monosomic dicephalia where the axial skeleton and internal organs were found to divide into parallel systems anterior to the pectoral girdle resulting in two well‐developed heads.     

Age,growth and reproductive biology of the silky shark,Carcharhinus falciformis,and the scalloped hammerhead,Sphyrna lewini,from the northwestern Gulf of Mexico

Synopsis The silky shark, Carcharhinus falciformis, and scalloped hammerhead, Sphyrna lewini, represent >80% of the shark by-catch of the winter swordfish/tuna longline fishery of the northwestern Gulf of Mexico. This catch represents a potential supplemental fishery, yet little is known of the life histories of the two species. This report relates reproductive biology data to age and growth estimates for 135 C. falciformis and 78 S. lewini. Unlike other regional populations, C. falciformis in the Gulf of Mexico may have a seasonal 12 month gestation period. Males mature at 210–220 cm TL (6–7 yr); females at >225 cm TL (7–9 yr). Application of age at length data for combined sexes produced von Bertalanffy growth model parameter estimates of L_∞ = 291 cm TL, K = 0.153, t₀ = −2.2 yr. Adult male S. lewini outnumbered adult females in catches because of differences in the distributions of the sexually segregated population. Males mature at 180 cm TL (10 yr); females at 250 cm TL (15 yr). von Bertalanffy parameter estimates for combined sexes of this species were L_∞ = 329 cm TL, K = 0.073, t_o = −2.2 yr.     

Spatial and temporal patterns of aboveground net primary productivity (ANPP) along two freshwater-estuarine transects in the Florida Coastal Everglades

We present here a 4-year dataset (2001–2004) on the spatial and temporal patterns of aboveground net primary production (ANPP) by dominant primary producers (sawgrass, periphyton, mangroves, and seagrasses) along two transects in the oligotrophic Florida Everglades coastal landscape. The 17 sites of the Florida Coastal Everglades Long Term Ecological Research (FCE LTER) program are located along fresh-estuarine gradients in Shark River Slough (SRS) and Taylor River/C-111/Florida Bay (TS/Ph) basins that drain the western and southern Everglades, respectively. Within the SRS basin, sawgrass and periphyton ANPP did not differ significantly among sites but mangrove ANPP was highest at the site nearest the Gulf of Mexico. In the southern Everglades transect, there was a productivity peak in sawgrass and periphyton at the upper estuarine ecotone within Taylor River but no trends were observed in the C-111 Basin for either primary producer. Over the 4 years, average sawgrass ANPP in both basins ranged from 255 to 606 g m⁻² year⁻¹. Average periphyton productivity at SRS and TS/Ph was 17–68 g C m⁻² year⁻¹ and 342–10371 g C m⁻² year⁻¹, respectively. Mangrove productivity ranged from 340 g m⁻² year⁻¹ at Taylor River to 2208 g m⁻² year⁻¹ at the lower estuarine Shark River site. Average Thalassia testudinum productivity ranged from 91 to 396 g m⁻² year⁻¹ and was 4-fold greater at the site nearest the Gulf of Mexico than in eastern Florida Bay. There were no differences in periphyton productivity at Florida Bay. Interannual comparisons revealed no significant differences within each primary producer at either SRS or TS/Ph with the exception of sawgrass at SRS and the C−111 Basin. Future research will address difficulties in assessing and comparing ANPP of different primary producers along gradients as well as the significance of belowground production to the total productivity of this ecosystem.     

First report of gastrocotylinean post-oncomiracidia (Platyhelminthes: Monogenoidea: Heteronchoinea) on gills of flyingfish (Exocoetidae), snapper (Lutjanidae), dolphinfish (Coryphaenidae), and amberjack (Carangidae) from the Gulf of Mexico: decoy hosts and the dilution effect

Larvae, identified as post-oncomiracidia of the suborder Gastrocotylinea (Monogenoidea), were collected from formalin-fixed gills excised from six species of marine fishes captured from the Gulf of Mexico off Mississippi and Florida: common dolphinfish, Coryphaena hippurus and pompano dolphinfish, Coryphaena equiselis (both Perciformes, Coryphaenidae); gray snapper, Lutjanus griseus (Perciformes, Lutjanidae); greater amberjack, Seriola dumerili (Perciformes, Carangidae); and Atlantic flyingfish, Cheilopogon melanurus and sailfin flyingfish, Parexocoetus hillianus (both Beloniformes and Exocoetidae). Based on a combination of diagnostic morphological features, the specimens were divided into two basic forms, each of which was further subdivided into two morphotypes. No gastrocotylinean post-oncomiracidium had been reported previously from these hosts. Of the six host species, only C. hippurus serves as a host (unconfirmed) for the adult of a gastrocotylinean species, suggesting that the recorded fishes from the Gulf of Mexico comprise dead-end hosts acting as decoys for the oncomiracidia. These comparatively non-susceptible “decoy hosts” apparently dilute the susceptible fish-host population and by intercepting infective larvae (oncomiracidia) decrease the abundance of parasites on their typical hosts.     

Conservation genetics of the alligator snapping turtle: cytonuclear evidence of range-wide bottleneck effects and unusually pronounced geographic structure

A previous mtDNA study indicated that female-mediated gene flow was extremely rare among alligator snapping turtle populations in different drainages of the Gulf of Mexico. In this study, we used variation at seven microsatellite DNA loci to assess the possibility of male-mediated gene flow, we augmented the mtDNA survey with additional sampling of the large Mississippi River System, and we evaluated the hypothesis that the consistently low within-population mtDNA diversity reflects past population bottlenecks. The results show that dispersal between drainages of the Gulf of Mexico is rare (F _STmsat  = 0.43, Φ_STmtDNA = 0.98). Past range-wide bottlenecks are indicated by several genetic signals, including low diversity for microsatellites (1.1–3.9 alleles/locus; H _e = 0.06–0.53) and mtDNA (h = 0.00 for most drainages; π = 0.000–0.001). Microsatellite data reinforce the conclusion from mtDNA that the Suwannee River population might eventually be recognized as a distinct taxonomic unit. It was the only population showing fixation or near fixation for otherwise rare microsatellite alleles. Six evolutionarily significant units are recommended on the basis of reciprocal mtDNA monophyly and high levels of microsatellite DNA divergence.     

<Emphasis Type="Italic">Clestobothrium gibsoni</Emphasis> n. sp. (Cestoda: Bothriocephalidae) from the bullseye grenadier <Emphasis Type="Italic">Bathygadus macrops</Emphasis> Goode &; Bean (Macrouridae) in the Gulf of Mexico

Clestobothrium gibsoni n. sp. is described from the intestine of the bullseye grenadier Bathygadus macrops (Macrouridae) collected in the northeastern Gulf of Mexico. The new species can be distinguished from both C. crassiceps (Rudolphi, 1819), the type-species of the genus, and C. neglectum (Lönnberg, 1893), the second species in the genus, by its unique ovary, which is transversely elongate and tapered on both ends rather than being U-or H-shaped, and by having more testes (60-65 vs 40-50 and 35-45 per proglottid). The new species is also compared to Bothriocephalus acheilognathi Yamaguti, 1934 and B. kivuensis Baer & Fain, 1954, two species with similar scoleces which have previously been assigned to Clestobothrium . The generic diagnosis of Clestobothrium is amended to include species with either anoperculate or operculate eggs. This is the first report of an adult tapeworm from a species of Bathygadus , and the first report of a species of Clestobothrium Lühe, 1899 (Bothriocephalidae) from the Gulf of Mexico.     

Organic Nitrogen Retention in the Atchafalaya River Swamp

Freshwater diversions from the lower Mississippi River into the region’s wetlands have been considered an alternative means for reducing nitrogen loading. The Atchafalaya River Swamp, the largest freshwater swamp in North America, carries the entire discharge of the Red River and 30% of the discharge of the Mississippi River, but it is largely unknown how much nitrogen actually can be retained from the overflowing waters of the Mississippi–Atchafalaya River system. Nitrogen discharge from the upper Mississippi River Basin has been implicated as the major cause for the hypoxia in the Northern Gulf of Mexico, which threatens not only the aquatic ecosystem health, but also Louisiana’s fishery industry, among other problems. This study was conducted to determine the change in organic nitrogen mass as water flows through the Atchafalaya River Swamp and into the Gulf of Mexico. By utilizing the river’s long-term discharge and water quality data (1978–2002), monthly and annual organic nitrogen fluxes were quantified, and their relationships with the basin’s hydrologic conditions were investigated. A total Kjeldahl nitrogen (TKN) mass input–output balance between the upstream (Simmesport) and downstream (Morgan City and Wax Lake Outlet) locations was established to examine the organic nitrogen removal potential for this large swamp. The results showed that on average, TKN input into the Atchafalaya was 200 323 tons year⁻¹ and TKN output leaving the basin was 145 917 tons year⁻¹, resulting in a 27% removal rate of organic nitrogen. Monthly TKN input and output in the basin were highest from March to June (input vs. output: 25 000 vs. 18 000 tons month⁻¹) and lowest from August to November (8000 vs. 6000 tons month⁻¹). There was a large variation in both annual and inter-annual organic nitrogen removals. The variability was positively correlated with the amount of inflow water at Simmesport, suggesting that regulating the river’s inflow at the Old River flood control structures may help reduce nitrogen loading of the Mississippi River to the Gulf of Mexico. Furthermore, the in-stream loss of organic nitrogen indicates that previous studies may have overestimated nitrogen discharge from the Mississippi–Atchafalaya River system.     

Paracapillaria epinepheli n. sp. (Nematoda: Capillariidae) from the red grouper Epinephelus morio (Pisces) from Mexico

A new nematode species, Paracapillaria epinepheli, is described from the stomach of the marine fish Epinephelus morio (Valenciennes), the red grouper, (Serranidae, Perciformes) from coastal waters of the Gulf of Mexico in Yucatan, southeastern Mexico. It is characterised mainly by its small body (body length of male and female 2.73–3.22 mm and 5.94–6.35 mm, respectively), number (31–36) and structure of the stichocytes, length of the spicule (0.180–0.195 mm), structure of the male caudal bursa (considerably reduced), structure and size of the eggs (size 0.057–0.063 × 0.027–0.030 mm), and by their site within the host. It is the second Paracapillaria species known to occur in the marine and estuarine fishes of the Gulf of Mexico.     

Moniligerum blairi n. g., n. sp. and Nudacotyle undicola n. sp. (Trematoda: Digenea) from the West Indian Manatee,Trichechus manatus L.

Moniligerum n. g. is erected for Moniligerum blairi n. sp. (Opisthotrematidae) and Nudacotyle undicola n. sp. (Nudacotylidae) is described, both from the small intestine of Trichechus manatus L. from Martin County, Florida. The new genus is placed in the family Opisthotrematidae Poche, 1926, subfamily Lankatrematinae Yamaguti, 1958. Moniligerum differs from other genera in the subfamily (Lankatrema Crusz & Fernand, 1954, and Lankatrematoides Blair, 1981) by the possession of an anterior collar and in the form of the ovary (compact and not transversely elongated) and vitellarium (single median lobed mass). Nudacotyle undicola differs from N. valdevaginatus, the most similar species, in body size, the length of the caeca, the shape of the vitellarium and the position of the genital pore, cirrus pouch and ovary.Supported in part by Cooperative Agreement No. 14-16-0008-1204 from the US Department of Interior, Fish and Wildlife Serivice. Florida Agricultural Experimental Stations Journal Series No. 3820.Supported in part by Cooperative Agreement No. 14-16-0008-1204 from the US Department of Interior, Fish and Wildlife Serivice. Florida Agricultural Experimental Stations Journal Series No. 3820.     

Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida, with comments on clinal variation

Age and growth rates of the bonnethead shark, Sphyrna tiburo, from northwest Florida were estimated from vertebrae collected between October 1992 and October 1995. The von Bertalanffy growth equation was fit to male and female vertebral age data. Initial growth was rapid (≈ 200 mm TL) for both sexes from age 0–1. At age 2 growth slowed for males but continued for females. Similar to many species of sharks, females grew slower than males (K = 0.28 and K = 0.69, respectively) but attained a larger maximum size (L_∞=1226 and L_∞=897). Maximum age was estimated in males and females to be 8+ and 12+ years, respectively. Growth of young-of-year sharks was 21 to 30 mm TL per month determined by three different methods. A comparison of age and growth estimates from populations at more southerly latitudes suggest that clinal variation in total length may be evident among bonnethead sharks in the Gulf of Mexico with females reaching larger sizes in northern areas as compared to south Florida. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mitochondrial and nuclear DNA analyses reveal fine scale geographic structure in bottlenose dolphins (<Emphasis Type="Italic">Tursiops truncatus</Emphasis>) in the Gulf of Mexico

There is a need for biological information to support current stock designations of bottlenose dolphins (Tursiops truncatus) in the Gulf of Mexico. The existence of many inshore, resident “communities” raises questions as to the relationship these dolphins may hold with dolphins inhabiting neighboring inshore and coastal areas. In this study, population subdivision was examined among four resident, inshore bottlenose dolphin stocks (Sarasota Bay, FL, Tampa Bay, FL, Charlotte Harbor, FL and Matagorda Bay, TX) and one coastal stock (1–12 km offshore) in the Gulf of Mexico. Evidence of significant population structure among all areas was found on the basis of both mitochondrial DNA (mtDNA) control region sequence data and nine nuclear microsatellite loci. Estimates of relatedness showed no population contained a significantly high number of related individuals, while separate AMOVAs for males and females indicated that both sexes exhibit a significant level of site philopatry. Results presented here provide the first genetic evidence of population subdivision between the coastal Gulf of Mexico and adjacent inshore areas along the central west coast of Florida. Such strong genetic subdivision is surprising given the short geographical distance between many of these areas and the lack of obvious geographic barriers to prevent gene flow. These findings support the current, separate identification of stocks for bottlenose dolphins inhabiting the eastern coastal and inshore areas of the Gulf of Mexico.     

An AFLP-based survey of genetic diversity among accessions of sea oats (Uniola paniculata, Poaceae) from the southeastern Atlantic and Gulf coast states of the United States

Uniola paniculata, commonly known as sea oats, is a C₄ perennial grass capable of stabilizing sand dunes. It is most abundant along the Gulf of Mexico and southeastern Atlantic coastal regions of the United States. The species exhibits low seed set and low rates of germination and seedling emergence, and so extensive clonal reproduction is achieved through production of rhizomes, which may contribute to a decline in genetic diversity. To date, there has been no systematic assessment of genetic variability and population structure in naturally occurring stands in the USA. This study was conducted to assess the genetic relationship and diversity among nineteen U. paniculata accessions representing eight states: Texas, Louisiana, Mississippi, Alabama, Florida, South Carolina, North Carolina, and Virginia, using amplified fragment length polymorphism (AFLP). Twelve AFLP EcoRI+MseI primer combinations generated a wide range of polymorphisms (42–81%) with a mean of 59%. Overall, the sea oats plants exhibited a low range of genetic similarity. Florida accessions, FL-33 and FL-39, were most genetically diverse and the accessions from both Carolinas and Virginia (NC-1, NC-11, SC-15, and VA-53) harbored less genetic variability. Cluster analysis using the UPGMA approach separated U. paniculata plants into four major clusters which were also confirmed by principal coordinate analysis (PCO). Further examination of the different components of genetic variation by analysis of molecular variance (AMOVA) indicated the largest proportion of variability at the state level (47.8%) followed by the variation due to the differences among the genotypes within an accession (34.4%), and the differences among the accessions within a state (17.8%). The relationship between genetic diversity and geographic source of sea oats populations of the United States as revealed through this comprehensive study will be helpful to resource managers and commercial nurseries in identifying suitable plant materials for restoration of new areas without compromising the adaptation and genetic diversity.     

First report of a sleeper shark (Somniosus sp.) in the southern Colombian Caribbean

A sleeper shark, genus Somniosus, was observed in the Colombian Caribbean. A Remote Operated Vehicle (ROV) recorded a sleeper shark specimen during an inspection while drilling a hydrocarbon exploratory well at 1,820 m water depth. This is the first record of a sleeper shark for the southern Colombian Caribbean. The previous most southern records of Somniosid sharks in the tropical and subtropical western Atlantic came from the western and northern Gulf of Mexico, and from Cuba.     

Description of Triaenorhina burti n. sp. (Cestoda: Paruterinidae) from the Malabar trogon Harpactes fasciatus (Pennant) (Aves: Trogoniformes: Trogonidae) in Sri Lanka

Triaenorhina burti n. sp. (Cyclophyllidea: Paruterinidae) is described from Harpactes fasciatus (Trogoniformes: Trogonidae) from the Southern Province of Sri Lanka. The new species is characterised by: a body 24–32 mm long; 44 rostellar hooks alternating in two closely adjacent regular rows, with lengths of 63–65 μm (anterior row) and 39–41 μm (posterior row); regularly alternating genital pores; testes divided into two groups by the ovary and vitellarium; a gravid uterus forming a single oval sac; and a cylindrical paruterine organ not reaching the anterior proglottis margin. A key to the seven recognised species of Triaenorhina Spasskii & Shumilo, 1965 is presented.     

The effect of environmental factors on the growth rate of Karenia brevis (Davis) G. Hansen and Moestrup

The red tide dinoflagellate Karenia brevis (Davis) G. Hansen and Moestrup is noted for causing mass mortalities of marine organisms in the Gulf of Mexico. Most research has focused on culture isolates from the eastern Gulf of Mexico. In this investigation, we examine the effects of light, temperature and salinity on the growth rate of K. brevis from the western Gulf of Mexico. Growth rates of K. brevis were determined under various combinations of irradiance (19, 31, 52, 67, and 123 μmol m⁻² s⁻¹), salinity (25, 30, 35, 40 and 45), and temperature (15, 20, 25, and 30 °C). Maximum growth rates varied from 0.17 to 0.36 div day⁻¹ with exponential growth rates increasing with increasing irradiance. Little or no growth was supported at 19 μmol photons m⁻² s⁻¹ for any experiment. Maximum growth rates at 15 °C were much lower than at other temperatures. Maximum growth rates of the Texas clone (SP3) fell within the range of Florida clones reported in the literature (0.17–0.36 div day⁻¹ versus 0.2–1.0 div day⁻¹). The Texas clone SP3 had a very similar light saturation point compared to that of a Florida isolate (Wilson's clone) (67 μmol m⁻² s⁻¹ versus 65 μmol m⁻² s⁻¹), and light compensation (20–30 μmol m⁻² s⁻¹1). The upper and lower salinity tolerance of the Texas clone was similar than that of some Florida clones (45 versus 46 and 25 versus 22.5, respectively). In our study, the Texas clone had the same temperature tolerance reported for Florida clones (15–30 °C). While individual clones can vary considerably in maximum growth rates, our results indicate only minor differences exist between the Texas and Florida strains of K. brevis in their temperature and salinity tolerance for growth. While the literature notes lower salinity occurrences of K. brevis in nearby Louisiana, our isolate from the southern Texas coast has the higher salinity requirements typical of K. brevis in the eastern Gulf of Mexico.     

Littorellicola billhawkinsi n. gen., n. sp. (Digenea: Aporocotylidae) from the myocardial lacunae of Florida pompano, Trachinotus carolinus (Carangidae) in the Gulf of Mexico; with a comment on the interrelationships and functional morphology of intertrabecular aporocotylids

Littorellicola billhawkinsi n. gen., n. sp. infects the myocardial lacunae of the ventricle and atrium of Florida pompano, Trachinotus carolinus in the northern Gulf of Mexico. It differs from other aporocotylid genera by the combination of having a body 10–30× longer than wide, a posterolateral body protuberance, lateral spine rows, an aspinous anterior sucker comprising a slightly muscular rim circumscribing the mouth, asymmetrical posterior ceca 14–20× length of the anterior ceca and lacking diverticula or secondary rami, tens of testes distributing in a cobblestone-like field anterior and posterior to the distal ends of the posterior ceca, an oviducal seminal receptacle comprising the distal portion of the oviduct, and a post-cecal ovary plus by lacking rosethorn-shaped spines, a pharynx, and a Laurer's canal. The new species appears host specific to Florida pompano because no conspecific infection was detected in 134 carangids of 8 species in 4 genera captured nearby the type locality. Psettarium sebastodorum Holmes, 1971 is transferred to the new genus, as Littorellicola sebastodorum (Holmes, 1971) n. comb., because it and the new species differ from species of Psettarium by the combination of having multiple testes plus 8 other features detailed herein. This report brings the number of nominal Gulf of Mexico aporocotylids to 12 species of 8 genera, represents only the second record of an aporocotylid from a carangid there, and supports the notion that elongated, “thread-like” aporocotylids with lateral spine rows are seemingly well-adapted for infecting myocardial lacunae or embedding in the myocardium of their definitive fish hosts.     

INCREASED SAMPLING FOR INFERRING PHYLOGEOGRAPHIC PATTERNS IN BOSTRYCHIA RADICANS/B. MORITZIANA (RHODOMELACEAE,RHODOPHYTA) IN THE EASTERN USA1

Zuccarello and West (2003) reported on the phylogenetic diversity of algae identified as Bostrychia radicans (Montagne) Montagne and B. moritziana (Sonder ex Kützing) J. Agardh from around the world. They showed that the species complex consisted of seven distinct lineages, of which two lineages were common on the East Coast of the USA and eastern Gulf of Mexico. The distribution of haplotypes within these lineages on the East Coast of the USA showed a general north–south distribution. One haplotype of lineage 5 (B) was mostly collected in northern areas, while the other common haplotype (C) was more southerly in distribution. Samples in lineage 6 (haplotype D) were not found north of Sapelo Island, Georgia. Increased sampling from the eastern USA over 5 years later has revealed an altered pattern. Haplotype D is distributed in North Carolina and is common in some populations. Haplotype C is rare or absent in many sampled populations. Haplotype B is only observed in the northern sampled sites on both sides of the Florida peninsula. This disjunct distribution agrees with geological scenarios for a strait between the western Gulf of Mexico and southern Georgia in the Miocene/Pliocene, which closed in the late Pliocene. This paper highlights the importance of increased sampling to determine phylogeographic patterns and hypotheses of dispersal scenarios in algae.