Introduction

The blenniid shorefish genus Ophioblennius is restricted to the tropical Atlantic and eastern Pacific Oceans. Springer (1962), based on limited material then available, recognized a single Atlantic species, O. atlanticus, the redlip blenny, and a single eastern Pacific species, O. steindachneri, the Panamic fanged blenny.

For each species Springer (1962), recognized two geographically distinct subspecies based on morphological differences. The Atlantic subspecies, O. a. macclurei, inhabits the Caribbean sea and coastal waters of the southeast U.S.; O. a. atlanticus has a broad geographical distribution, ranging north to the Azores, south to St. Helena Island and Brazil, west to the western Caribbean, and east to the west coast of Afica.

More recently, a molecular study (Muss, et. al. 2000) examined the phylogeography of Ophioblennius by comparing a 630-bp region of mitochondrial cytochrome b for 171 individuals from ten Atlantic and eastern Pacific localities. Their results suggest that Ophioblennius comprises six lineages, one Pacific, O. steindachneri, and five Atlantic, which are geographically distributed as follows: 1) Brazil, 2) Caribbean/western Atlantic, 3) Saõ Tomé, 4) Azores/Cape Verde, and 5) mid-Atlantic. The purpose of the present study was to determine if there are morphological features that support the recognition of five species of Atlantic Ophioblennius.

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Methods

Three methods of data collection were used in this study:

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RADIOGRAPHY

Radiography was done using a digital X-ray setup, which enables images to be edited and retrieved quickly. The numbers of dorsal- and anal-fin elements, and vertebrae, were counted from radiographs of 280 specimens. (Figure 1)

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CLEARING AND STAINING

Clearing and Staining is a process in which soft tissue beneath the skin is enzymatically digested, bones are stained red, and cartilage is stained blue. The result is a clearly visible skeleton that can be dissected and studied in three dimensions. The gill arches, suspensorium, pectoral girdle, and caudal skeleton were viewed for 19 cleared and stained specimens. (Figure 2)

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WHOLE-SPECIMEN EXAMINATION

Whole-specimen examination involved careful observation of an entire preserved specimen, with or without the aid of a microscope, to identify morphological differences. The main aspects of external morphology studied were pigment patterns on the head, dorsal-, anal-, caudal- and pectoral fins. (Figure 3)

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Results

Five anatomically distinct groups were discovered (See Lineage Map, above):

1) Caribbean/ western Atlantic - lower lip and lower pectoral-fin rays white* (Figure 4); modally two fewer vertebrae and two fewer dorsal- and anal-fin elements than all other Ophioblennius (Table 1)
*White areas in preserved specimens are red in life.

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2) Senegal - Chin with unique pattern of chevron-shaped bands of pigment (Figure 5)

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3) Brazil - Posterior margin of operculum white; distal half of only first 2-3 dorsal-fin elements light, remaining elements with only distal tips (Figure 6). Note: compare with Figure 4 in which distal halves of all anterior dorsal fin elements are light.

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4) Azores/ Canaries/ Madeira post-ocular spot > 80% of eye diameter (Figure 7)

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5) Ascension/ St. Helena - Caudal fin mostly dark, only distal portions of several rays of upper caudal lobe pale (Figure 8)

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Note: No supporting evidence for these groups was found in the cleared and stained specimens. However, a feature in the gill arches supports the separation of Atlantic and Pacific lineages. All Atlantic specimens have a large foramen in the third pharyngobranchial whereas O. steindachneri does not (Figure 9).

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Conclusions

1) Five geographically distinct groups are recognizable by morphology: 1) Caribbean/western Atlantic, 2) Brazil, 3) Azores/Canaries/Madeira, 4) Ascension/St. Helena, 5) Senegal.

2) Four of those lineages correlate well with lineages identified based on genetic data: 1) Caribbean/ western Atlantic, 2) Brazil, 3) Azores, 4) Ascension/St. Helena.

3) A fifth lineage was recognized in each study: Saõ Tomé, by genetic data and Senegal, by morphology. Pigment patterns were not assessable in available preserved specimens from Saõ Tomé (or the Cape Verdes), and the molecular study did not include specimens from Senegal (or the Canaries and Madeira). Further molecular and morphological study is thus needed to clarify the number of lineages present in the eastern Atlantic.

4) At least five species of Ophioblennius should be recognized in the Atlantic; names are available in the literature for the following:

If future molecular study corroborates our hypothesis that the Canary, Madeira and Azores populations represent a single species, this species will be named O. atlanticus, which has priority over O. webbi.

5) A new name is needed for the Ascension/St. Helena species, and one or more names will be needed for the Saõ Tomé/Cape Verde/Senegal lineage or lineages. We tentatively propose the name Ophioblennius caligocauda for the Ascension/St. Helena species based on the predominantly dark caudal fin.

6) Future studies of shorefishes with similar distributions could greatly increase overall estimates of biodiversity for marine shorefishes in the Atlantic.

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Acknowledgements

I would like to thank the following people and organizations for their endearing support of this project and myself: Dr. Carole Baldwin, Dr. Victor G. Springer, Alla Mauke, Dr. Jeffrey T. Williams, Sandra Raredon, Julie Mounts, Dylan Fawcett, the rest of the fishes staff, The National Science Foundation, and The Research Training Program. For providing specimens for this study from throughout the Atlantic, we thank M. de Pinna, P. Buckup, R. Moura, R. Vari, C. Stepien, P. Wirtz, K. Hartel, S. Schaefer, R. Fricke, E. Anderson, and M. Biscoito.

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ENTOMOLOGY

Sarah Garrett
"An Inventory of Leafroller Species of Moths of the Great Smoky Mountains National Park"

Abstract / Summary

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