New genus and species of Aporocotylidae (Digenea) from a basal actinopterygian, the American paddlefish, Polyodon spathula, (Acipenseriformes: Polyodontidae) from the Mississippi Delta

Acipensericola petersoni n. gen., n. sp. (Digenea: Aporocotylidae) infects the heart of the American paddlefish Polyodon spathula (Walbaum, 1792) in the Mississippi Delta. It has robust, spike-like body spines arranged in ventrolateral transverse rows; a bowl-shaped anterior sucker centered on the mouth and having minute spines on the inner anteroventral surface only; a pharynx; an inverse U-shaped ceca extending to near the posterior body end; intercecal testes comprising a pre-ovarian testicular column plus a single testis posteriorly; an extensively lobed ovary located medially and immediately posterior to the testicular column; a spherical ootype that is intercecal and post-ovarian; a Laurer's canal; and a common genital pore. The new species is the first-named aporocotylid collected from a basal actinopterygian. It resembles the chondrichthyan aporocotylids Chimaerohemecus trondheimensis, Orchispirium heterovitellatum, and Hyperandrotrema cetorhini in having an inverse U-shaped ceca, but it is morphologically most similar to the anguilliform aporocotylid Paracardicoloides yamagutii in having that feature plus a comparable anterior sucker, a single testis posteriorly, an intertesticular ovary, and a common genital pore. Sequence data for the complete small subunit ribosomal DNA (18S) do not refute its membership within Aporocotylidae nor its affinity to 1 of those aforementioned aporocotylids: A. petersoni was basal to the few teleost aporocotylids analyzed, and C. trondheimensis was the only taxon basal to A. petersoni. We regard the specimens of Spirorchis sp. previously reported from the shortnose sturgeon Acipenser brevirostrum Lesueur, 1818 as congeneric with the new species.     

Evidence that a lineage of teleost-infecting blood flukes (Aporocotylidae) infects bivalves as intermediate hosts

The family Aporocotylidae is recognized as having the widest intermediate host usage in the Digenea. Currently, intermediate host groups are clearly correlated with definitive host groups; all known life cycles of marine teleost-infecting aporocotylids involve polychaetes, those of freshwater teleost-infecting aporocotylids involve gastropods, and those of chondrichthyan-infecting aporocotylids involve bivalves. Here we report the life cycle for a marine elopomorph-infecting species, Elopicola bristowi Orélis-Ribeiro & Bullard in Orélis-Ribeiro, Halanych, Dang, Bakenhaster, Arias & Bullard, 2017, as infecting a bivalve, Anadara trapezia (Deshayes) (Arcidae), as the intermediate host in Moreton Bay, Queensland, Australia. The cercaria of E. bristowi has a prominent finfold, distinct anterior and posterior widenings of the oesophagus, a tail with symmetrical furcae with finfolds, and develops in elongate to oval sporocysts. We also report molecular data for an unmatched aporocotylid cercaria from another bivalve, Megapitaria squalida (G. B. Sowerby I) (Veneridae), from the Gulf of California, Mexico, and six unmatched cercariae from a gastropod, Posticobia brazieri (E. A. Smith) (Tateidae), from freshwater systems of south-east Queensland, Australia. Phylogenetic analyses demonstrate the presence of six strongly-supported lineages within the Aporocotylidae, including one of elopomorph-infecting genera, Elopicola Bullard, 2014 and Paracardicoloides Martin, 1974, now shown to use both gastropods and bivalves as intermediate hosts. Of a likely 14 aporocotylid species reported from bivalves, six are now genetically characterised. The cercarial morphology of these six species demonstrates a clear distinction between those that infect chondrichthyans and those that infect elopomorphs; chondrichthyan-infecting aporocotylids have cercariae with asymmetrical furcae that lack finfolds and develop in spherical sporocysts whereas those of elopomorph-infecting aporocotylids have symmetrical furcae with finfolds and develop in elongate sporocysts. This morphological correlation allows predictions of the host-based lineage to which the unsequenced species belong. The Aporocotylidae is proving exceptional in is propensity for major switches in intermediate host use, with the most parsimonious interpretation of intermediate host distribution implying a minimum of three host switches within the family.     

Two new species of Cardicola (Digenea: Sanguinicolidae) in drums (Sciaenidae) from Mississippi and Louisiana

Two new species of Cardicola (Digenea: Sanguinicolidae) are described from the heart of drums (Perciformes: Sciaenidae) in and off Mississippi and Louisiana. Cardicola palmeri n. sp. infects the black drum, Pogonias cromis, and, in mature individuals, is distinguished from its congeners by the combination of a body 1.9-2.9 times longer than wide, an esophagus 44-52% of the body length, posterior ceca 1.0-1.8 times longer than the anterior ones, a gland encircling the seminal vesicle that is 30-37% of maximum body width in diameter, and a sinistral and nearly medial male pore. Cardicola currani n. sp. infects the red drum, Sciaenops ocellatus, and is distinguished from its congeners by the combination of posterior ceca 1.8-4.2 times longer than anterior ones, a male pore located well posterior to the ootype, a female pore and transverse metraterm located just anterior to the level of the ootype, and a medial and posttesticular ovary located at the level of the terminal ends of the posterior ceca. No adult blood fluke had been described previously from the northern Gulf of Mexico west of Florida. Each of the 2 flukes infected only 1 host species despite the hosts being sympatric.     

Cardicola opisthorchis n. sp. (Trematoda: Aporocotylidae) from the Pacific bluefin tuna, Thunnus orientalis (Temminck & Schlegel, 1844), cultured in Japan

A new aporocotylid blood fluke is described, based on specimens from the ventricle of the Pacific bluefin tuna, Thunnus orientalis (Temminck et Schlegel), cultured in Wakayama and Nagasaki Prefectures, Japan. The new species is morphologically similar to the members of the genus Cardicola Short, 1953, but shows distinct differences in the body form, location of the testis and the orientation of the ootype. The body of the new species is long and slender, whereas other Cardicola species are small and generally lanceolate. The testis is mostly located posterior to the caeca and anterior to the ovary, occupying 31–45% of body length, in contrast to the known Cardicola species, whose testis is typically intercaecal. The ootype is oriented anteriorly, while in most congeners, it is directed posteriorly or horizontally. Phylogenetic analyses of this aporocotylid, together with Cardicola orientalis Ogawa, Tanaka, Sugihara et Takami, 2010 from the same host, were conducted based on DNA sequences of the ITS2 rDNA and the 28S region of ribosomal RNA. The analyses revealed that the new blood fluke belongs to the genus Cardicola despite the marked morphological differences. Thus, this aporocotylid is named Cardicola opisthorchis n. sp. and the generic diagnosis is emended in this paper. In addition, 100% identity among the ITS2 sequences from the present species, Cardicola sp. from T. orientalis in Mexico and Cardicola sp. from the northern bluefin tuna, Thunnus thynnus (Linnaeus) in Spain suggests that C. opisthorchis n. sp. has a broad geographical distribution and that it infects both the Pacific and northern bluefin tuna.     

Blood flukes (Digenea: Aporocotylidae) of stingrays (Myliobatiformes: Dasyatidae): Orchispirium heterovitellatum from Himantura imbricata in the Bay of Bengal and a new genus and species of Aporocotylidae from Dasyatis sabina in the northern Gulf of Mexico

We redescribe Orchispirium heterovitellatum based on the holotype and 3 original voucher specimens collected from the mesenteric blood vessels of scaly whiprays Himantura imbricata (Bloch and Schneider, 1801) (as Dasyatis imbricatus) captured in the western Bay of Bengal off Waltair, India. We emend the diagnosis of Orchispirium to include anterior sucker present, testis looping, cirrus sac enveloping large internal seminal vesicle, oviducal seminal receptacle present, and metraterm short and thin-walled. We describe Myliobaticola richardheardi n. gen., n. sp. based on live observations, light microscopy, and scanning electron microscopy of adult specimens collected from between the cardiac trabeculae of Atlantic stingrays Dasyatis sabina (Lesueur, 1824) captured in Mississippi Sound (type locality), Mississippi, and Apalachicola Bay, Florida. The new species has a minute, aspinous body lacking lateral tubercles; an aspinous and eversible anterior sucker lacking a peduncle; a posterior esophageal swelling; an inverse U-shaped intestine; smooth ceca terminating in the anterior body half; a looping testis lacking lobes; a cirrus sac enveloping a large internal seminal vesicle; a medial and primarily post-testicular ovary; an oviducal seminal receptacle; a postgonadal uterus flanking the internal seminal vesicle; a short and thin-walled metraterm; and a common genital pore. It lacks a pharynx and Laurer's canal. No other named aporocotylids infect a member of cohort Batoidea or have the combination of an aspinous body, an aspinous anterior sucker, a posterior esophageal swelling, an inverse U-shaped intestine, a looping testis, a cirrus sac enveloping a large internal seminal vesicle, and a common genital pore; these observations indicate that O. heterovitellatum and M. richardheardi are closely related. The discovery of a second species representing a second genus of Aporocotylidae in diamond stingrays (Dasyatidae) suggests that Batoidea is an undersampled host group for aporocotylid infections.     

A new genus and species of Brachycoeliidae (Digenea) from Chiropterotriton sp. (Caudata: Plethodontidae) in Mexico and its phylogenetic position within the Plagiorchiida based on partial sequences of the 28S ribosomal RNA gene

Parabrachycoelium longicaecum n. gen., n. sp. (Digenea: Brachycoeliidae) is described from the intestine of a plethodontid salamander Chiropterotriton sp. Hosts were collected in bromeliads at the cloud forest of Tlaquilpa, Veracruz, Mexico. Members of the Brachycoeliidae Looss, 1899 (sensu Yamaguti, 1971) are characterized by having a spined tegument; ceca usually short, not passing level of gonads, but longer in some species; gonads posterior to, or in region of, acetabulum, with ovary anterior to testes; a well developed cirrus pouch containing a bipartite seminal vesicle; and uterus occupying entire hind-body posterior to testes. However, this combination of morphological traits prevents the inclusion of the new taxon in any of the genera in that family; a new genus was, therefore, erected to accommodate the new species. The new taxon is readily distinguished from members belonging to Brachycoelium Dujardin, 1845, Mesocoelium Odhner, 1910, and Tremiorchis Mehra and Negi, 1925, by having long ceca extending into the posterior third of the body, slightly surpassing the testes, and vitellaria extending along the body. The new species morphologically resembles Caudouterina rhyacotritoni Martin, 1966, a digenean parasitizing a plethodontid salamander; however, the latter species lacks spines in the tegument and is actually placed within the Allocreadiidae. To demonstrate further the phylogenetic position of the new taxon, we sequenced the D1-D3 regions of 28S rRNA gene and conducted a phylogenetic analysis of available sequences for the order to which brachycoeliids belong (Plagiorchiida). Sequence divergence of the partial 28S rRNA gene confirms its distinction from the aforementioned brachycoeliids, and the phylogenetic position within the Plagiorchiida places the new species as closely related to a clade formed by Brachycoelium + Mesocoelium. Divergence levels and phylogenetic position within the Plagiorchiida verifies the validity of the new genus and its inclusion in Brachycoeliidae.     

A new aporocotylid (Digenea) species from blood vascular system of gag grouper, Mycteroperca microlepis (Perciformes: Serranidae), off Alabama, with an emendation of Pearsonellum Overstreet & Køie, 1989

Pearsonellum lemusi n. sp. (Digenea: Aporocotylidae) infects the blood vascular system of the gag grouper, Mycteroperca microlepis (Perciformes: Serranidae), in the north central Gulf of Mexico, approximately 80 km south of Dauphin Island, Alabama (29°34'09″N, 88°22'16″W). The new species can be most easily differentiated from its only congeners Pearsonellum corventum Overstreet and K?ie, 1989 (type species) and Pearsonellum pygmaeus Nolan and Cribb, 2004 , both of which infect Australian serranids, by the combination of having a large adult body (3,237 × 570 μm), a cecal intersection comprising an elongated medial channel, anterior ceca >10% of total body length, ovary narrower than testis, and pre-ovarian uterus not looping between testis and ovary. The embryonated eggs of the new species infect gill epithelium, are spheroid, and measure 25-30 μm in diameter. Sympatric Gulf of Mexico serranids were negative for aporocotylid infections: coney, Cephalopholis fulva (n = 1); Nassau grouper, Epinephelus striatus (3); red grouper, Epinephelus morio (32); yellowedge grouper, Epinephelus flavolimbatus (1); rock hind, Epinephelus adscensionis (1); red hind, Epinephelus guttatus (2); Warsaw grouper, Epinephelus nigritus (3); graysby, Cephalopholis cruentata (1); black grouper, Mycteroperca bonaci (1), and tattler, Serranus phoebe (2). The new species is the first aporocotylid described from a serranid outside of the southwestern Pacific Ocean. The diagnosis of Pearsonellum Overstreet and K?ie, 1989 is herein emended to include anterior sucker having concentric rows of spines anterior to mouth, pharynx absent, esophagus length <1/2 total body length, vas deferens connecting with cirrus sac anteromedially, ovary occupying posterior 1/4-1/3 of body, primary vitelline duct dextral, and oviducal seminal receptacle extending posteriad in parallel with lateral body margin, not transverse nor constricted anteriorly or posteriorly by sharp bends or kinks.     

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.     

Morphological and molecular data reveal a new species of Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) from Dormitator maculatus in the Gulf of Mexico

Neoechinorhynchus (Neoechinorhynchus) mexicoensis sp. n. is described from the intestine of Dormitator maculatus (Bloch 1792) collected in 5 coastal localities from the Gulf of Mexico. The new species is mainly distinguished from the other 33 described species of Neoechinorhynchus from the Americas associated with freshwater, marine and brackish fishes by having smaller middle and posterior hooks and possessing a small proboscis with three rows of six hooks each, apical hooks longer than other hooks and extending to the same level as the posterior hooks, 1 giant nucleus in the ventral body wall and females with eggs longer than other congeneric species. Sequences of the internal transcribed spacer (ITS) and the large subunit (LSU) of ribosomal DNA including the domain D2 + D3 were used independently to corroborate the morphological distinction among the new species and other congeneric species associated with freshwater and brackish water fish from Mexico. The genetic divergence estimated among congeneric species ranged from 7.34 to 44% for ITS and from 1.65 to 32.9% for LSU. Maximum likelihood and Bayesian inference analyses with each dataset showed that the 25 specimens analyzed from 5 localities of the coast of the Gulf of Mexico parasitizing D. maculatus represent an independent clade with strong bootstrap support and posterior probabilities. The morphological evidence, plus the monophyly in the phylogenetic analyses, indicates that the acanthocephalans collected from intestine of D. maculatus from the Gulf of Mexico represent a new species, herein named N. (N.) mexicoensis sp. n.     

Plagioporus wataugaensis n. sp. (Digenea: Opecoelidae) infecting intestine of northern hogsucker,Hypentelium nigricans,and white sucker,Catostomus commersonii, (Cypriniformes: Catostomidae) from the eastern USA,including an emended diagnosis,key to Nearctic congeners,and phylogenetic analysis

We describe a new species of Plagioporus Stafford, 1904 infecting the intestine of two catostomids in the eastern USA. We emend Plagioporus to account for Nearctic congeners having ceca terminating at the level of the testes (previously diagnosed as having ceca terminating in the post-testicular space only) and testes in the posterior body extremity (a feature not previously considered as having generic importance). Of the accepted Nearctic species, Plagioporus wataugaensis n. sp. resembles Plagioporus serotinus Stafford, 1904, Plagioporus hypentelii Hendrix, 1973, and Plagioporus hageli Fayton and Andres, 2016 but differs from them by the distribution of the vitellarium and proportional length and relative extent of the excretory vesicle. Plagioporus wataugaensis has vitelline fields that are discontinuous at the level of the ventral sucker (vs. continuous in P. serotinus and P. hypentelii) and follicles that surround the ceca (vs. wholly ventral to the ceca in P. hageli) and that span the midline dorsal to the testes (vs. slightly overlapping the lateral margins of the testes). The excretory vesicle of P. wataugaensis is wholly post-testicular and short (6–9% of the body length) (vs. reaching the level of the posterior testis, 14–24% of the body length). Phylogenetic analyses of the 28S, ITS1, 5.8S, and ITS2 rDNA recovered P. wataugaensis sister to Plagioporus sinitsini Mueller, 1934. A key to the Nearctic Plagioporus spp. is provided. We regard Plagioporus shawi (McIntosh, 1939) Margolis, 1970, Plagioporus serratus Miller, 1940, and Plagioporus loboides (Curran, Overstreet, and Tkach, 2007) Fayton and Andres, 2016 as incertae sedis.     

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Acanthocephala: Neoechinorhynchidae) from the freshwater fish Awaous banana (Valenciennes) (Gobiidae) in Mexico

Neoechinorhynchus (Neoechinorhynchus) chimalapasensis n. sp. (Eoacanthocephala: Neoechinorhynchidae) is described from the intestine of Awaous banana (Valenciennes) (Pisces: Gobiidae) collected in the Río Negro, a tributary in the upper Río Coatzacoalcos basin, Santa María Chimalapa, Oaxaca State, Mexico. It is the third species of Neoechinorhynchus Stiles & Hassall, 1905 described from Mexican freshwater fishes, although 36 other species are known from freshwater fishes in the Americas. Like four other species of Neoechinorhynchus from freshwater fishes in North America and Mexico, N. (N.) limi Muzzall & Buckner, 1982, (N.) rutili (Müller, 1780) Stiles & Hassall, 1905, N. (N.) salmonis Ching, 1984 and N. (N.) roseus Salgado-Maldonado, 1978, males and females of the new species are less than 20 mm in length, lack conspicuous sexual dimorphism in size, have a small proboscis of about 0.1 mm in length with the largest hooks being the anteriormost, about 30–90 μm in length and of equal size, and have subequal lemnisci, larger than the proboscis receptacle but still relatively short and, in males, generally restricted to a position considerably anterior to the testes. The new species is closest to N. (N.) roseus, but it is distinguished from it by having: (1) a slightly larger cylindrical proboscis with almost parallel sides versus a globular proboscis with a rounded tip which is shorter and somewhat wider in N. (N.) roseus; (2) smaller but robust anterior proboscis hooks that do not reach the equatorial level or extend beyond the hooks of the middle circle as in N. (N.) roseus; and (3) the female gonopore situated ventrally subterminal, as opposed to being a significant distance anteriorly to the posterior extremity in N. (N.) roseus.     

Three new intestinal protozoan species of the genus Latteuria n.g. (Ciliophora: Trichostomatia) from Asian and African elephants

Three new ciliate species presumably belonging to the family Paraisotrichidae were recognized in the fecal samples from zoo-kept Asian and African elephants. All the ciliates possess a unique but similar arrangement of somatic ciliature, thus a new genus Latteuria n.g. has been created for them. The genus is characterized by the presence of a tapered frontal ‘spout’ at the anterior end of the body, posterior ciliary rows in narrow grooves encircling the posterior half of the body and an anterior arch of cilia. Latteuria polyfaria n.sp. is the largest species in the genus with 9–11 posterior ciliary rows. In L. media n.sp., of medium body size, the number of rows varies from four to six, and the smallest species, L. trifaria n.sp., has only three-four posterior ciliary rows.     

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.     

Chaulioleptos haywardi n. gen., n. sp. (Digenea: Sanguinicolidae) from Filimanus heptadactyla (Perciformes: Polynemidae) of Moreton Bay, Australia

Here we describe the first species of sanguinicolid blood fluke (Trematoda: Digenea) from a polynemid fish. Chaulioleptos haywardi n. gen., n. sp. is described from Filimanus heptadactyla Cuvier, 1829 (Perciformes: Polynemidae), the sevenfinger threadfin from Sandgate, Moreton Bay (southeast Queensland, Australia). Chaulioleptos haywardi differs from existing sanguinicolid genera in the combined possession of the following 7 characters: 2 testes, an entirely postovarian uterus, a uterine chamber, separate genital pores, an H-shaped intestine with abbreviated anterior caeca, tegumental spines in incomplete ventro-marginal transverse rows that are continuous along the length of the body, and vitelline follicles that are tightly compacted and subsequently appear to form a solid branching mass occupying the area anterior to intestinal bifurcation and extending posteriorly to the level of the posterior margin of the anterior testis. Chaulioleptos haywardi is most closely related to Paracardicola Martin, 1960 and Adelomyllos Nolan and Cribb, 2004.     

The sexual adult of Cercaria praecox Walker, 1971 (Digenea: Fellodistomidae), with the proposal of Oceroma n. g.

A sexual adult trematode that is considered to be conspecific with the distinctive larval trematode Cercaria praecox Walker, 1971 is reported from the kyphosid fish Scorpis lineolata Kner in Moreton Bay, Queensland, Australia. The sexual adult is consistent with the cercarial body of Cercaria praecox in having a single caecum with an asymmetrical appendix, symmetrical testes immediately posterior to the ventral sucker, and the ovary and vitellarium both well posterior to the testes. This combination of characters is distinct within the Fellodistomidae Nicoll, 1909 and requires the proposal of a new genus, Oceroma n. g. Analysis of 28S rDNA sequences demonstrates that this species forms a clade with Coomera Dove & Cribb, 1995 within the Fellodistomidae. The life-cycle of the species is predicted to require two hosts and to involve the direct ingestion of the cercaria.     

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.     

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.