• Abstract and Figures
• Public Full-text

AN ABSTRACT OF THE THESIS OF Carl Albert Forss for the Ph. D. in Zoology (Name) (Degree) (Major) 1q1:1) Date thesis is presented l k` -} 1.-(2.t 1 Title THE OPLOPHORID AND PASIPHAEID SHRIMP FROM OFF THE OREGON COAST Redacted for Privacy Abstract approved (Major Professor) The 13 species of shrimps studied for this thesis were collected off the Oregon coast. The family Oplophoridae is well represented in this area. Five of the seven known genera were identified. Hymenodora frontalis, H. glacialis, and H. gracilis were described and further differentiating characters were illustrated. Other mem- bers of the family Oplophoridae were illustrated and described as follows: Acanthephyra curtirostris, Meningodora mollis, Notostomus japonicus, Systellaspis braueri and S. cristata. Species of the family Pasiphaeidae, although less well repre- sented, were identified. The presence or absence of the mandibular palp in these two species, Parapasiphaë sulcatifrons and P. cristata, found to be of little systematic value in separating them. Specimens with a carapace length of 7- 10mm lack a mandibular palp; one with a carapace length of 17 -25mm had a two -segmented palp. Pasiphaea pacifica, P. magna, and P. chacei were identified and illustrated. The taxonomy, geographical distribution, color and luminescence are discussed. THE OPLOPHORID AND PASIPHAEID SHRIMP FROM OFF THE OREGON COAST by CARL ALBERT FORSS A THESIS submitted to OREGON STATE UNIVERSITY in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY June 1966 APPROVED: Redacted for Privacy Professor of Zoology In Charge of Major Redacted for Privacy Chairman of Zoology Department Redacted for Privacy Dean of Graduate School Date thesis is presented ¿,C.,C-( .u%C ; . 9'612' Typed by Marcia Ten Eyck ACKNOWLEDGEMENT The present study has been made possible by a NSF Grant No GB 1588; U. S. Atomic Energy Commission Contracts ÁT(45- 1)1726 and ÁT(45- 1)1750, administered by Dr. William G. Pearcy, Department of Oceanography, Oregon State University. My sincerest thanks are extended to Dr. Pearcy. A special word of thanks is tendered Dr. John C. Yaldwyn, of the Australian Museum, Sidney. He most graciously made many essential identifications and added helpful remarks to his identifica- tions of the troublesome species. I wish to thank Dr. Ivan Pratt, my major Professor of the Department of Zoology, Oregon State University, for space, facilities and advice. TABLE OF CONTENTS Page INTRODUCTION 1 METHODS . 2 SYSTEMATIC DISCUSSION 3 General Considerations 3 Key to the Oregon Genera of Pasiphaeidae 6 Key to the Oregon Species of Pasiphaea 6 Pasiphaea pacifica 7 Pasiphaea magna 8 Pasiphaea chacei 9 Parapasiphaë sulcatifrons 11 Parapasiphaë cristata 13 Key to the Genera of Oplophorids off Oregon 16 Acanthephyra curtirostris 17 Meningodora mollis . 19 Notostomus japonicus . 21 Key to the Oregon Species of Hymenodora 23 Hymenodora frontalis .. 23 Hymenodora glacialis . 25 Hymenodora gracilis 27 Key to the Species of Systellaspis 29 Systellaspis braueri 30 Systellaspis cristata 32 GENERAL DISCUSSION AND SUMMARY 34 Taxonomy 34 Geographical Distribution 35 Color of Bathypelagic Caridea 36 Luminescence 37 TABLE OF CONTENTS Continued Page BIBLIOGRAPHY 38 APPENDIX . 43 THE OPLOPHORID AND PASIPHAEID SHRIMP FROM OFF THE OREGON COAST INTRODUCTION In 1961 the Department of Oceanography, Oregon State University, undertook a long term ecological study of the Oregon coast. Out of this study were obtained several unusual bathypelagic Caridea and Penaeidea taken between 0- 1000m. The topography and physical characteristics of the near -shore waters probably are responsible in part, for the distribution of the shrimps to be discussed. Vertical migration among decapods has been known for some time to occur (Murray and Hjort 1912, Chace 1940 and Bainbridge 1961). Vertical migration also occurs for the shrimps taken off the Oregon coast. Of the forms considered herein, tows to 200m caught predom- inately a carid shrimp, Pasiphaea pacifica. In tows to 500m P. pacifica was nearly absent, Hymenodora frontalis was taken quite frequently. Even at depths to 1000m almost no P. pacifica were taken, although H. frontalis was common. The few day tows that were taken brought up only a limited number of shrimps, indicating that these species avoid the surface waters during daylight by moving into deeper waters. 2 METHODS The nektonic organisms were sampled with a six -foot Isaacs - Kidd midwater trawl (Isaacs and Kidd, 1953). Most of the sampling was done in the upper 0 -200m depth. The sampling was done at night except for a few tows taken during daylight hours. The net was lowered rapidly for tows from 0 -200m and then retrieved at a con- stant speed of 30m per minute. For tows to 500m the trawl was fished between 500 and 200m for about 30 minutes, and for tows to 1000m the trawl was fished between 1000 and 500m for one hour. The net was open at all depths since no opening - closing device was used. All the collections were made from the R/V Acona. Records for all collections were made such as geographic position at the start and end of each tow, towing time, speed and environmental conditions. Samples were preserved aboard ship in 10% formalin. Identification was in the laboratory ashore. Drawings were made with the aid of a Wild's camera lucida and a Bio- scope. 3 SYSTEMATIC DISCUSSION GENERAL CONSIDERATIONS: The Decapoda (Crustacea) is divided into Reptantia and Natantia. The latter are the shrimps, which characteristically have a large antennal scale and five pairs of biramous pleopods on the abdomen. The abdomen is chitinized, with pleura and a complete tail -fan. In the natantians (swimmers) the antennal scale is generally large and lamellar; five pairs of characteristically biramous (rarely uniramous) pleopods present, always well developed and used for swimming; abdomen always macrurous (i. e. symmetrical, well chitinized, with pleura and complete tail -fan). Shrimps and prawns. The suborder Natantia is divided into three sections: Caridea, Stenopodidea and Penaeidea. These sections usually have been termed tribes. This term, however, cannot be used for them, since during the 14th International Congress of Zoology at Copenhagen, 1953, it was decided that the term tribe is to be used only for units below the subfamily level. The three sections may be distinguished as follows: la. Pleurae of second abdominal somite overlapping those of first and third segments. No chelae on the third pereiopods. Gills phyllobranchiate . Caridea 4 b. Pleurae of second abdominal somite not overlapping those of first segment. Third legs with a chela. 2a 2a. Third leg distinctly stronger than the preceding. Males without petasma. Gills trichobranchiate. Stenopodidea b. Third leg never stronger than the preceding, generally all chelipeds of equal strength. Males with petasma. Gills dendrobranchiate Penaeidea The carapace in all cases is measured from its dorsal posterior margin to the posterior margin of the eye orbit. In order to determine sex in the Caridea it was necessary to observe the inner ramus of the first pleopod in the family Oplo- phoridae. The first pleopod in the males is modified into the appendix masculina, the inner ramus of pleopods II through V are nearly the same in appearance. In the family Pasiphaeidae it was necessary to observe the inner ramus of the second pleopod, which was the loca- tion of the appendix masculina. The inner ramus of all pleopods in the female are similar and their margins edged with long setae. Order Decapoda Suborder Natantia Section Caridea 5 Superfamily Pasiphaeoida Family Pasiphaeidae Rostrum a normal forward - directed prolongation of the carapace or absent; if absent, it is represented by an erect postfrontal spine. Fingers of all four chelae slender with their cutting edges pectinate. Exopods present on all pereiopods; reduced or absent on second maxilliped. Mandible without a molar process and with or without a mandibular palp. REMARKS: The family Pasiphaeidae includes at present seven genera, two of which have been taken off the Oregon coast; Pasiphaea Savigny (1816) and Parapasiphaë Smith (1884). Pasiphaea is a cosmopolitan genus, the 36 species except P. chacei Yaldwyn having been found in almost all oceans of the world. The above exception is a newly described species. Two of the three species, P. pacifica Rathbun and P. chacei, are bathypelagic, taken in depths to 1000m. P. magna Faxon has been taken only by otter trawl at depths of greater than 2000m. Of the seven species of Parapasiphaë, two have been taken off the Oregon coast; P. cristata Smith and P. sulcatifrons Smith. This is the first record of these species occurring in the Pacific Ocean. 6 The only other species of this genus taken in the Pacific Ocean is P. serrata Rathbun. KEY TO THE OREGON GENERA OF PASIPHAEIDAE: 1. Rostrum a post - frontal spine; no mandibular palp. Pasiphaea 2. Rostrum a normal forward projection, arising from the frontal margin of the carapace; mandibular palp present in mature forms Parapasiphaë Genus Pasiphaea Savigny, 1816 Rostrum represented by a post -frontal projecting spine. Orbits poorly defined. Mandibule without a palp. KEY TO THE OREGON SPECIES OF PASIPHAEA: la. Telson forked or notched; carapace arising into a sharp pointed tooth above the anterior gastric region; branchio- stegal spine not reaching anterior margin of carapace. P pacifica b. Telson truncate; rostrum projecting beyond anterior margin of carapace; branchiostegal spine reaches anterior margin of carapace 2a 7 2a. Telson terminating in four pairs of spines; rostrum long and slender; branchiostegal spine projects well beyond the anterior margin of the carapace P. chacei b. Telson terminating in six pairs of spines and a small medial unpaired spine; rostrum heavy, triangular in shape; branchiostegal spine reaches anterior portion of carapace. P magna Pasiphaea pacifica Rathbun, 1902 Pasiphaea pacifica Rathbun, 1902, p. 905. Pasiphaea pacifica Rathbun, 1904, p. 20, fig. 2. Pasiphaea pacifica Richardson, 1908, p.

Load more

  61

Copy Link