THE COMPARISON OF TWO UNDESCRIBED SPECIES OF SKATES, BATHYRAJA SP. 2 AND BATHYRAJA SP (C.F. EATONII) FROM THE ANTARCTIC WATERS OF THE SOUTH ORKNEY ISLANDS by Heather Kalisz A Thesis Submitted to the Faculty of The Wilkes Honors College in Partial Fulfillment of the Requirements for the Degree of Bachelor of Arts in Liberal Arts and Sciences with a Concentration in Marine Biology Wilkes Honors College of Florida Atlantic University Jupiter, Florida May 2013 THE COMPARISON OF TWO UNDESCRIBED SPECIES OF SKATES, BATHYRAJA SP. 2 AND BATHYRAJA SP (C.F. EATONII) FROM THE ANTARCTIC WATERS OF THE SOUTH ORKNEY ISLANDS by Heather Kalisz This thesis was prepared under the direction of the candidate’s thesis advisor, Dr. Jon Moore, and has been approved by the members of his/her supervisory committee. It was submitted to the faculty of The Honors College and was accepted in partial fulfillment of all the requirements for the degree of Bachelor of Arts in Liberal Arts and Sciences. SUPERVISORY COMMITTEE: ____________________________ Dr. Jon Moore ____________________________ Dr. Nicholas Quintyne ____________________________ Dean Jeffery Buller, Wilkes Honors College _______________ Date ii ACKNOWLEDGEMENTS I would like to thank Dr. Jon Moore of Florida Atlantic University for giving me the opportunity to conduct my research on both the Bathyraja sp. 2 and Bathyraja c.f. eatonii specimens, allowing me access to the laboratory and tools needed to conduct the research, and for being my thesis advisor. I would also like to thank Dr. Nicholas Quintyne for being on my thesis committee and assisting me in improving my thesis. iii ABSTRACT Author: Heather Kalisz Title: The comparison of two undescribed species of skates, Bathyraja sp. 2 and Bathyraja sp. (c.f. eatonii) from the Antarctic waters of the South Orkney Islands Institution: Wilkes Honors College of Florida Atlantic University Thesis Advisor: Dr. Jon Moore Degree: Bachelor of Arts in Liberal Arts and Sciences Concentration: Marine Biology Year: 2013 Skates of the genus Bathyraja belong to the subfamily Arhynchobatinae in the family Rajidae. This family is comprised currently of 228 recognized species and about 50 unnamed species (McEachran and Dunn, 1998). Some authors elevate the Arhynchobatidae to the rank of family (Nelson, 2006). Two unnamed species of skates Bathyraja sp. 2 and Bahtyraja cf. eatonii were examined and measured in the preparation of formally describing these species. A total of 20 preserved specimens of Bathyraja sp. 2 and a total of 4 preserved specimens of Bathyraja cf. eatonii, collected during the 2008- 2009 AMLR survey cruise of the South Orkney Islands, were measured. The measurements of each skate were taken following the measurement descriptions in Hubbs and Ishiyama (1968). The body proportions of B. sp. 2 and B. cf. eatonii were compared and contrasted and a preliminary species description of each species is given. iv To Anita and Robert Bottoms, for without you, I would not be who I am I Love You TABLE OF CONTENTS Introduction ……………………………………………………………………………….1 Materials and Methods ……………………………………………………………………8 Results …………………………………………………………………………………...19 Discussion ……………………………………………………………………………….21 References ……………………………………………………………………………….26 v LIST OF TABLES 1. Illustrates the corresponding station numbers, date, latitude, longitude, and average depth for the specimens. The data used to create this table contains information provided by Jones et al., (2009). ……………………………………………………...9 2. Illustrates the Specimen I.D number (tissue tag numbers) from Table 1 and the correlating catalog numbers for each specimen. …………………………………….10 3. The proportional dimensions are expressed in percentages of disc width and total length. This table was created using the same format as Springer, 1971. …………..20 vi LIST OF FIGURES 1. Smith et al., (2008) Illustrates through a phylogenetic tree the relation between Bathyraja sp. 2 (in this research it is known as Bathyraja sp. (dwarf)) and Bathyraja cf. eatonii. ……………………………………………………………………………7 2. Illustrates the station locations, particularly station numbers 15, 89, 21, 24, 27, 73, and 5 from Leg II of the 2008-2009 AMLR survey, from which the studied specimens were collected. These stations are all located in the South Orkney Islands (Jones et al., 2009). ……………………………………………………………………………..8 3. Photograph of a preserved specimen from the AMLR 2008-2009 survey cruise, Bathyraja sp. 2. Photograph credit: Heather Kalisz ………………………………...12 4. Photograph of a preserved specimen from the AMLR 2008-2009 survey cruise, Bathyraja cf. eatonii. Photograph credit: Heather Kalisz …………………………...13 5. Technical terms and method of measurements referred to and used in the study of skates (from Stehmann and Bürkel, 1990; originally found in Stehmann 1981). …...14 vii Introduction: Skates belong to the suborder Rajoidea and are typically placed in the family Rajidae (McEachran and Dunn, 1998) or split between the families Rajidae and Arhynchobatidae (Nelson, 2006). Skates are unique to the class of cartilaginous fishes, Chondrichthyes, due to their high species diversity yet low morphological differences (McEachran and Dunn, 1998). Fishes of the family Rajidae, as characterized by McEachran and Dunn (1998), range in size from 20-30 cm to more than 2 m in total length (Stehmann, 1981) and are located worldwide in marine waters ranging from the shoreline to 3000 m in depth, but are not found in the Pacific plate or the Red Sea (McEachran and Dunn, 1998). There are currently 228 recognized species and about 50 unnamed species (McEachran and Dunn, 1998). The following is the description of the characteristics given to the family Rajidae (Skates) by Stehmann (1985) in the FAO species identification sheets of the Southern Ocean. The Rajidae fishes have a body consisting of the head, trunk, and enlarged pectoral fins, which are dorsoventrally flattened forming a rhombic to roundish disc. Their pectoral fins are completely fused to the sides of the head and trunk from tip or the midlength of the snout to the insertion of the pelvic fins. The tail is moderately slender, yet distinctly marked off from the disc, and its length is less than two times the disc width, with a narrow fold (lateral tail fold) along each of the tail’s edges. The eyes and spiracles are located on the dorsal side of the body. The spiracles are located immediately behind the eyes and include a pseudobranchial fold at their anterior wall. Stehmann, (1985), also stated that the shape of the snout can range from acutely angled and long to obtusely rounded and short. The front of the cranium is extended in most species as a 1 rostral process, which can be stout or delicate, and in the latter case can be segmented distally or basally. The anterior pectoral fin rays and their basal elements are either extending almost to tip of the snout (soft-snouted species, with a delicate or even reduced rostral process) or to about the midlength of the snout only (hard-snouted species with a stout rostral process). The transverse mouth gap located on the ventral side of the body is straight to more or less arched in shape. There are numerous rows of teeth present in bands on the upper and lower jaws and are obtuse or pointed in shape, showing sexual dimorphism in many species. The teeth bands are placed in a pavement pattern also known as quincunx, in parallel rows, or in a combination of both. The nasal apertures are small and located shortly anterior of the mouth on the ventral side. The nasal aperture’s inner margins expand rearward as a large bilobed nasal curtain with both lobes joined to form a broad transverse isthmus, which is close to the front of the mouth and basally fused to the upper jaw. The pelvic fins of the Rajidae family are bilobed with the two lobes separated externally by a more or less deep notch in their outer margins only. On the tail there are two small dorsal fins on the far posterior end. A caudal fin is also present at the most posterior end of the tail, as well as a rudimentary ventral fold or keel is also sometimes present. The dorsal surface of the skin is densely to sparsely set with spinules (prickles) and often thornlets and or thorns are present too. The pattern of the spinules, thornlets, and/or thorns consists of an arrangement of patches, rows, and/or single tubercles in distinct regions. There is at the minimum a median row of thorns present along the midline of the tail (except in some species of Malacoraja), and sometimes extending forward onto the midline of the back. Malar and alar thorns on the lateral portions of the disc may also be developed in sexually mature males only. The 2 ventral surface of the skin is smooth to more or less prickley, rarely also with some irregularly distributed thorns. Patterns of spinules, thornlets, and thorns may vary with growth, age, and sexual maturity. The dorsal color of skates is in nearly all shades of grey to brown. A few species are reddish, or blue-violet, and coloration can occur in many different patterns. The ventral surface may be uniformly dark or light, or mottled, or a light centre of the disc with dark edges, while some species have darkly pigmented pores. Deep water skates can, as a rule, be characterized as plain dark on both surfaces, whereas shallow-water species are predominately white ventrally and often extremely variegated on the dorsal surface. The color pattern may vary with the nature of the bottom substrate and also with growth and age. According to McEachran and Dunn (1998), the characters that help distinguish the Rajidae from all other batoids include: oviparous development; alar and/or malar thorns in mature males; lateral muscle bundles of tail converted into electric organs; second hypobranchial cartilage fused with basibranchial cupula; anterior portion of 2nd hypobranchial cartilage absent, therefore 2nd hypobranchial cartilage lacks articulation with 2nd ceratobranchial; clasper skeleton with dorsal terminal cartilage; clasper skeleton with ventral terminal cartilage.