Micah Bakenhaster

Florida Fish and Wildlife Conservation Commission, Florida City, Florida, United States

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Publications (14)20.92 Total impact

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    ABSTRACT: Based on light and scanning electron microscopical studies, three new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from marine fishes of the genus Lutjanus Bloch (Perciformes: Lutjanidae) in the northern Gulf of Mexico: P. longispicula sp. n. from the ovary of the northern red snapper L. campechanus (Poey) (type host) and silk snapper L. vivanus (Cuvier); P. latispicula sp. n. from the ovary and rarely testes of the grey snapper L. griseus (Linnaeus); and P. synagridis sp. n. (only males available) from the ovary of the lane snapper Lutjanus synagris (Linnaeus). These species are mainly characterised by the lengths of spicules (378-690 microm, 135-144 microm and 186-219 microm, respectively) and spicule shapes, structure of the distal portion of the gubernaculum and the structure of the male caudal end. These are the first valid, nominal species of gonad-infecting philometrids reported from fishes of the family Lutjanidae in the western Atlantic region.
    Folia parasitologica 08/2014; 61(4):355-69. · 2.52 Impact Factor
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    ABSTRACT: The parasitic nematode Philometra floridensis infects the ovary of its only host, the economically important fish species Sciaenops ocellatus, but the factors influencing host susceptibility and potential pathogenic effects are unknown. Here we report new information on these topics from evaluations of infected and uninfected hosts collected from the northeastern Gulf of Mexico. Fish length and age were evaluated vis-à-vis nematode prevalence to check for ontogenetic differences in host susceptibility. To evaluate health and reproductive consequences of infection, we looked for effects in Fulton's condition factor (K) and batch fecundity estimates (BF), and we evaluated ovarian tissue histologically to check for oocyte atresia and other host responses. We observed localized pathological changes in fish ovarian tissue associated with female nematodes, including leucocytic exudates, granulomatous inflammation, and Langhans-type multinucleated giant cells; the hosts, however, appeared to maintain high fecundity and actually exhibited, on average, better health index scores and higher relative fecundity than did uninfected fish. These differences are likely explained by the parasite's tendency to disproportionately infect the largest, actively spawning fish and by the localization of pathogenic changes, which could have masked effects that otherwise would have been reflected in mass-based health indicators. Although we did not detect negative effects on measures of overall health or reproductive output, further research is needed to better elucidate the relationship between these parasites and other factors affecting host reproductive potential, such as egg quality.
    Diseases of Aquatic Organisms 04/2014; 108(3):227-39. · 1.73 Impact Factor
  • František Moravec, Micah Bakenhaster
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    ABSTRACT: Based on light and scanning electron microscopical studies, two new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from marine perciform fishes in the northern Gulf of Mexico: P. hyporthodi n. sp. from the ovary of the yellowedge grouper Hyporthodus flavolimbatus (Poey) (Serranidae) and P. lopholatili n. sp. from the ovary of the great northern tilefish Lopholatilus chamaeleonticeps Goode & Bean (Malacanthidae). Philometra hyporthodi is mainly characterised by the body length of both the males (3.62-4.07 mm) and gravid female (105 mm), the length of the spicules (135-138 μm) and the presence of dorsal transverse lamella-like structures on the distal portion of the gubernaculum. Philometra lopholatili is distinguished by the presence of a distinct dorsal protuberance consisting of two dorsolateral lamellated parts separated from each other by a smooth median field, an uninterrupted mound on the male caudal extremity, the length of the spicules (165-189 μm) and the body length of the males (2.19-2.34 mm) and gravid female (280 mm). Philometra lopholatili is the first representative of the genus and the second philometrid species reported from fishes of the family Malacanthidae.
    Systematic Parasitology 10/2013; 86(2):113-23. · 1.26 Impact Factor
  • Frantisek Moravec, Micah Bakenhaster, Isaure de Buron
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    ABSTRACT: Abstract A new nematode species, Philometra atlantica n. sp. (Philometridae), is described from male and female specimens found in the ovary of the Atlantic Spanish mackerel, Scomberomorus maculatus (Mitchill) (Scombridae, Perciformes), off the Atlantic coast of Florida and South Carolina. Based on light and scanning electron microscopy examination, the new species differs from most other gonad-infecting Philometra spp. in the length of spicules (111-126 µm), number and arrangement of genital papillae, and a U-shaped, dorsally interrupted caudal mound in the male. A unique feature among all gonad-infecting philometrids is the presence of 2 reflexed dorsal barbs on the distal end of the gubernaculum. From a few congeneric, gonad-infecting species with unknown males, it can be distinguished by some morphological and biometrical features found in gravid females (body length, length of first-stage larvae or esophagus, structure of caudal end) and by the host type (fish family) and geographical distribution. Philometra atlantica is the 4th valid gonad-infecting species of Philometra reported from fishes of the family Scombridae.
    Journal of Parasitology 10/2012; · 1.32 Impact Factor
  • František Moravec, Micah Bakenhaster
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    ABSTRACT: The following 3 species of Philometra Costa, 1845 (Nematoda: Philometridae) were recorded from marine fishes off Florida: Caranginema americanum Moravec, Montoya-Mendoza and Salgado-Maldonado, 2008 from the subcutaneous tissue of the crevalle jack Caranx hippos (Linnaeus) (Carangidae); Philometra charlestonensis Moravec, de Buron, Baker and González-Solís, 2008 from the gonads (ovaries) of the scamp Mycteroperca phenax Jordan and Swain (Serranidae); and Philometra sp. (only subgravid females) from the gonads (ovaries) of the Atlantic needlefish Strongylura marina (Walbaum) (Belonidae). The male of C. americanum , the type species of Caranginema Moravec, Montoya-Mendoza, and Salgado-Maldonado, 2008 , is described for the first time. Its general morphology is similar to that of males of Philometra and Philometroides species. The males of C. americanum are mainly characterized by an elongate body, 3.13-3.28 mm long, a markedly elongate esophagus, and spicules and a gubernaculum 69-75 µm and 48-51 µm long, respectively. The present findings of C. americanum and P. charlestonensis represent new geographical records. The gonad-infecting Philometra sp. from S. marina probably belongs to an undescribed species.
    Journal of Parasitology 10/2011; 98(2):398-403. · 1.32 Impact Factor
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    Delane C. Kritsky, Willis J. McAleese, Micah D. Bakenhaster
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    ABSTRACT: Examination of the gills of 10 crevalle jack, Caranx hippos (Linnaeus) (Carangidae), from the northeastern portion of Florida Bay, Everglades National Park, Florida revealed 3 species of Heteronchoinea (Monogenoidea): Protomicrocotyle mirabilis (MacCallum, 1918) Johnston & Tiegs, 1922 (Gastrocotylinea, Protomicrocotylidae) (prevalence  =  80%; intensity  =  2–16 parasites/host; mean intensity  =  7 parasites/host); Allopyragraphorus hippos (Hargis, 1956) Yamaguti, 1963 (Microcotylinea, Allopyragraphoridae) (80%; 1–8; 3.5); and Cemocotyle noveboracensis Price, 1962 (Microcotylinea, Cemocotylidae) (80%; 1–100; 35.3). Two crevalle jack (standard length 139–140 mm) were uninfected; 3 (standard length 154–183 mm) had mean intensities (all parasite species) of 14.3 (intensity  =  5–20) parasites per host; 5 larger hosts (standard length  =  312–395 mm) were more heavily infected with the 3 parasite species (mean intensity  =  63.8 [intensity  =  16–109] parasites per host). Protomicrocotyle mirabilis is redescribed and figured; A. hippos is considered a valid species and distinct from Allopyragraphorus incomparabilis (MacCallum, 1917) Yamaguti, 1963 (previously considered synonyms); and C. noveboracensis is distinguished from congenerics in part by lacking a haptoral lappet.
    Comparative Parasitology 07/2011; · 0.88 Impact Factor
  • Delane C Kritsky, Stephen A Bullard, Micah D Bakenhaster
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    ABSTRACT: 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.
    Parasitology International 04/2011; 60(3):274-82. · 2.30 Impact Factor
  • Delane C Kritsky, Micah D Bakenhaster
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    ABSTRACT: Examination of the gill lamellae of three sheepshead Archosargus probatocephalus (Walbaum) from the Indian River Lagoon in Florida revealed six species of Monogenoidea: Microcotyle archosargi MacCallum, 1913 (Microcotylidae); Neobenedenia sp. (Capsalidae); and four new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae). The prevalence of all helminths was 100%, except for Neobenedenia sp., which was represented by a single immature specimen. The four new species, Euryhaliotrema carbuncularium n. sp., E. dunlapae n. sp., E. amydrum n. sp. and E. spirulum n. sp., are described and with E. carbunculus (Hargis, 1955) Kritsky & Boeger, 2002 apparently constitute a monophyletic clade of Euryhaliotrema spp. that parasitise sparid hosts in the western hemisphere. The Indian River Lagoon in Florida represents a new locality record for M. archosargi, and the sheepshead is apparently a new host record for a member (Neobenedenia sp.) of the Capsalidae.
    Systematic Parasitology 01/2011; 78(1):57-68. · 1.26 Impact Factor
  • František Moravec, Micah Bakenhaster
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    ABSTRACT: A new nematode species, Philometra diplectri n. sp. (Philometridae), is described from male and female specimens found in unidentified tissues of head and anterior trunk (males) and subcutaneously in the mouth and under the operculum (females) of sand perch, Diplectrum formosum (Linnaeus) (Serranidae, Perciformes), from the northern Gulf of Mexico off Florida (Florida Middle Grounds). Based on light and scanning electron microscopy examination, the new species differs from other congeners parasitizing the subcutaneous tissues, fins, tissues of the buccal cavity, and gill covers or gill arches of marine and brackish-water fishes, mainly in having 8 conspicuously large cephalic papillae of the external circle, the absence of caudal projections, and the shape and small size of the anterior inflation of the esophagus in gravid females, and in possessing 5 pairs of caudal papillae and spicules 66-78 µm long in males. Philometra diplectri is the first known species of this genus whose gravid females are parasitic in the head tissues of serranid fishes.
    Journal of Parasitology 10/2010; 96(5):987-92. · 1.32 Impact Factor
  • Frantisek Moravec, Micah Bakenhaster
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    ABSTRACT: The following three species of the Philometridae (Nematoda: Dracunculoidea) are described from marine perciform fishes of the Everglades National Park (northern Gulf of Mexico), Florida, U.S.A.: Philometra brevispicula sp. n. (male and females) from the subcutaneous tissue of mouth of the gray snapper Lutjanus griseus (Linnaeus) (Lutjanidae), Philometroides grandipapillatus sp. n. (only females) from pectoral fin muscle of the crevalle jack Caranx hippos (Linnaeus) (Carangidae), and Caranginema americanum Moravec, Montoya-Mendoza et Salgado-Maldonado, 2008 (females) from the subcutaneous fascia of trunk muscle in crevalle jack C. hippos. Philometra brevispicula is mainly characterized by small cephalic papillae of the external circle, the absence of oesophageal teeth and the presence of small caudal projections in gravid female, markedly short spicules (45 microm) in male, and by its location in the host. Philometroides grandipapillatus differs from congeners mainly in the shape of the cephalic region (narrow, conspicuously protruding), large cephalic papillae of the external circle and the absence of caudal projections in female, and by the site of infection in the host. Caranginema americanum is for the first time recorded from the northern Gulf of Mexico.
    Folia parasitologica 09/2010; 57(3):213-22. · 2.52 Impact Factor
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    ABSTRACT: Examination of the gill lamellae of 3 species of Centropomus spp. (Centropomidae) from 9 localities around the southern coast of Florida revealed 3 species of Rhabdosynochus (Monogenoidea, Diplectanidae). The common snook, Centropomus undecimalis, was infected with Rhabdosynochus rhabdosynochus (30 of 37 infected; prevalence 81%), Rhabdosynochus hargisi (9 of 37; 24%), and Rhabdosynochus hudsoni (20 of 37; 46%); the fat snook, Centropomus parallelus, with R. rhabdosynochus (12 of 22; 55%) and R. hudsoni (8 of 22; 36%) (new host records for both); and the tarpon snook, Centropomus pectinatus, with R. hudsoni (3 of 4; 75%) (new host record). Snooks infected with R. rhabdosynochus were collected only from tidal waters of salinity ≤10.4 ppt, where the parasite dominated the monogenoidean community. Rhabdosynochus hargisi and R. hudsoni showed greater salinity tolerance; the former dominated where salinity was ≥28.8 ppt. Thus, salinity appears to be a determinate factor in partitioning the monogenoidean community, while water depth and temperature and host population (as defined by collection locality) did not appear to affect occurrence of Rhabdosynochus spp. on snooks in Florida. With the exception of Tampa Bay for R. hargisi , each locality represented a new geographic record for the respective diplectanid. The type species, R. rhabdosynochus, is redescribed based on specimens collected from its type host, C. undecimalis.
    Journal of Parasitology 05/2010; 96(5):879-86. · 1.32 Impact Factor
  • F Moravec, E J Fajer-Avila, M Bakenhaster
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    ABSTRACT: A new nematode species, Philometra floridensis sp. n. (Philometridae), is described from male and female specimens found in the ovary of red drum, Sciaenops ocellatus (Linnaeus) (Sciaenidae, Perciformes), from the Gulf of Mexico off Treasure Island, Florida, USA. Based on light and scanning electron microscopy examination, the new species differs from most other gonad-infecting Philometra spp. in having a smooth gubernaculum with a distinct dorsal tooth on the distal tip. The new species is most similar to P. carolinensis Moravec, de Buron & Roumillat, 2006, but differs in length and shape of spicules. It can be distinguished from P. carolinensis and other species with unknown males, by the markedly greater body length of gravid females (up to about 100 cm). Philometra floridensis is the third valid gonad-infecting species of Philometra reported from sciaenids.
    Journal of Helminthology 08/2009; 84(1):49-54. · 1.16 Impact Factor
  • Micah D. Bakenhaster, Richard S. McBride, W. Wayne Price
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    ABSTRACT: This research examines the life cycle of the parasitic cymothoid isopod Glossobius hemiramphi and its role as a symbiont with its fish host, ballyhoo (Hemiramphus brasiliensis). Samples of H. brasiliensis were collected from July 1997 to October 1998 in nearshore waters of south Florida. Fish were randomly culled from a commercial lampara net fishery, and independent of the fishery, fish were collected with cast nets or hook and line. The average parasite prevalence was 10.1%, observed in 2,928 fish collected year round. Monthly prevalence ranged from 4.6 to 18.2% and was highest in the summer on small young-of-the-year fish. Prevalence declined with fish size from a high of 38.0% for fish 11-16 cm to a low of 3.3% for fish 28-29 cm. Ovigerous females were observed throughout the year and no within-brood mortality was evident. Marsupiumites developed through five distinct ontogenetic stages, and the final marsupial stage (manca) was likely immediately infestive upon release. Diminutive males (2.8-12.4 mm) were attached to the host's gill arches, and larger females (16.9-35.6 mm) occupied the buccal cavity. Only a single fish older than age-1 was infested. These results indicate that Glossobius hemiramphi is a protandric hermaphrodite with an annual life cycle. There was no evidence of a parasitic effect on the host fish condition (weight-length), but we cannot exclude the possibility that infested fish have a higher mortality rate than uninfested fish, at least temporarily (1 year).
    Journal of Crustacean Biology 01/2009; · 1.02 Impact Factor
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    ABSTRACT: A new species of nematode, Philometra morii sp. nov. (Philometridae), is described from males and gravid females collected from the mouth cavity of the red grouper, Epinephelus morio (Valenciennes) (Serranidae, Perciformes), from the northen Gulf of Mexico, off Florida, USA. The new species is characterized mainly by the length of spicules (84–90 and 72–87 μm) and the length (54 μm) and structure of the gubernaculum in the male, and by the presence of three large oesophageal teeth protruding from the mouth, the number and arrangement of small cephalic papillae (8 papillae in 4 pairs of external circle and 6 single papillae of internal circle), the length (1.09–1.50 mm) and structure of the oesophagus and two large papilla-like caudal projections, and by the length of their bodies (19.34–30.07 mm). Philometra morii is the third species of this genus reported from E. morio in the Gulf of Mexico, differing from the two previously described species, in addition to morphological features, by the site of infection in this host (mouth cavity and sinuses vs oculo-orbits or gonads). From the same region (northern Gulf of Mexico, off Florida), gravid females of Philometra Costa, 1845, morphologically and biometrically similar to those of P. morii, were found in the subcutaneous tissues and sinuses of the head of another serranid fish (gag), Mycteroperca microlepis (Good et Bean). Although their conspecificity with P. morii cannot be excluded, they have been designated as Philometra sp. until conspecific males are discovered and described. Based on light and scanning electron microscopy examination (latter used only for females), both these forms are described. KeywordsParasitic nematode- Philometra -marine fish- Epinephelus - Mycteroperca -Gulf of Mexico-Florida
    Acta Parasitologica 55(4):359-368. · 1.00 Impact Factor

Publication Stats

41 Citations
20.92 Total Impact Points

Institutions

  • 2009–2013
    • Florida Fish and Wildlife Conservation Commission
      • Fish and Wildlife Research Institute
      Florida City, Florida, United States
    • Academy of Sciences of the Czech Republic
      • Biology Centre
      Praha, Hlavni mesto Praha, Czech Republic
    • The University of Tampa
      Tampa, Florida, United States
  • 2011
    • Idaho State University
      • Department of Health and Nutrition Sciences
      Pocatello, ID, United States