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BULLETIN DE L'INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE, BIOLOGIE, 75: 5-20, 2005 BULLETIN VAN HET KONI NKLIJK BELGISCH INSTITUUT VOOR NATUURWETENSCHAPPEN, BIOLOGIE, 75: 5-20, 2005
Contributions to the odontological study of living ChondrichthY,es. 2. The genus Oxynotus RAFINESQUE, 1810
by J. HERMAN, M. HOVESTADT-EULER & D.C. HOVESTADT
Abstract: The tooth morphology of three of the four species of the Material genu s Oxynotus is described and partl y illustrated by SEM photo graphs. An interspecifi c diagno sis reveals the tooth morphol ogical For thi s stu dy , fo ll owing material was avai lable : Oxynotus differences between th e species 0. bmniensis, 0. centrina and 0. bruniensis : two males, Oxynotus centrina: 13 males and 16 paradoxus. females , Oxynotus paradoxus: 5 males and 3 females . Key words: Odontology - Chondrichthyes - Squaliformes - Oxynotidae - Oxynotus - Tooth morphology. Oxynotus RAFINESQUE, 1810 Resume: La morphologie dentaire de trois des quatre especes du genre 0.\)'nollts est decrite et fi guree partiellement a !'aide de cl i The genus Oxynotus compri ses four species : 0 .bruniensis ches MEB . Une diagnose interspec ifiq ue precise les differences morphologiques dentaires observees entre les especes 0. (OGILB Y, 1893), 0. caribbaeus, CERY IGON , 196 1, the type bruniensis, 0. centrina et 0 . parado.xus. species 0. centrina (LINNAEUS , 175 8) and 0 . paradoxus FR ADE, 1929. Mots-des: Odontologie - Chondrichth yes - Squali formes - Oxynotidae- O.~J · n olt.ls- Morphologie dent aire . Oxynotus bruniensis (OGILBY, 1893) Kurzfassung: Di e Zahnmorphologie vo n drei vo n der vier Arten OGILBY J.D ., 1893 : Centrina bruniensis. Records of th e der Gattung Oxynotus werden besc hrieben und teilweise illustri ert Australian Museum. Sidney. 2(5) :62-63. mit REM Photos. Eine interspezifisc he Di agno se zeigt die zahn Textplates I ,2, plates I to 3 morphologische Unterschi ede zwischen den Arten 0 . bruniensis, '~ 0. cemrina und 0. paradoxus. For the first schematic illustrati on uf upper and lower teeth Schliisselworter: Odontologie- Chondri chthyes - Squali formes see GARRICK J.A.F. , . 1960 : Studies on New Zealand Oxynotidae - Oxynotus- Zahnmorphologie. Elasmobranchii . XI. Squaloids of the genera Deania, Etn wpterus, Oxynotus and Dalatias in New Zealand waters. Tran saction of th e royal Society of New Zealand. Wellington. Introduction 88(3): 51 9-557,6 figs. For a second one, with correct illustrations of outer faces of With the excepti on of 0 . centrina, the tooth morphol ogy of one upper tooth and one lower tooth see LAST P.R. & the taxa of the genu s Oxynotus is poorl y kn ow n. For thi s STEVENS J.D. , 1994 : Sharks and Rays ofAustralia. CSIRO study tooth materi al was avai lab le of 0 . bruniensis, 0. division of Fisheries. Sidney. 513p., 84pl. (cf. p. 105). centrina and 0 . paradoxus. Due to lacking tooth samples of 0 . caribbaeus thi s species could not be incorporated in this This species shows a strong dignathic heterodonty and a study. The tooth morph ology of 0 . bruniensis and 0. weak monognathi c heterodonty. The root is always paradoxus will be described and illustrated. 0 . centrina, anau lacorhi zid . which was described and illustrated by HER1vlAN, The dimensions of the lower teeth are subcentrimetrical, HOYESTADT-EULER & HOYESTADT ( 1989), wi ll be used here those of the upper teeth plurimilimetri cal in size. and more information, as well as more illustrati ons are pro vided. An interspecific di ffe renti al di agnos is reveals their UPPER JAW tooth morphological differences. For the terminology used here, see HER MAN, HOYESTADT-EULER and HOVESTADT The teeth are compressed, havin g a more or less verticall y 1989. elongated crow n and root. ,,
6 J. HERMAN, M. HOVESTADT-EULER & D.C. HOVESTADT
Textplate 1 : Oxynotus bnmiensis (OGILBY, 1893). Male 560mm t.l., caught off Wollongon, New-South-Wales, Australia. Outer view of two upper left anterior teeth and the whole lower left toothset
Textplate 2 : Oxynotus bruniensis (OGILBY, 1893). Male 560mm t.l. , caught off Woll ongon, New-South-Wales, Australi a. Diagraph of the same lower left toothset. I I
Contributi ons to the odontological study of li vin g Chondrichthyes I ? 7
The crown is twice as hi gh as the crown base width and as UPPER JAW hi gh as the root. The symphyseal tooth has a symmetri cal tri angul ar crown. The lateral teeth maintain symmetri cal, The teeth are compressed, havin g a more or less verticall y less hi gh, and narrower toward the commissure. Both mesial elongated crown and root. and distal cutting edges are smooth. The height of the crown is twice as high as the crown base The outer face is strongly convex and a broad apron extends width , but half the root height. The symphyseal tooth has a nearl y to the root base. The apron is arched at the base and symmetri cal tri angul ar crown. The lateral teeth show a slightly overhangs the root. A true outer or inner ornamenta crown, becoming increasingly asym m~ tri ca l , less hi gh, and tion is absent. broader based toward the commissure. Both mesial and di stal The root is elongated and has a more or less rectangular ap cutting edges are smooth . pearance. The basal edges of the root are sli ghtl y rounded. A The outer face is strongly convex and a broad apron extends fo ramen is present at each side of the apron. The inner face is nearl y to the root base. The apron is not overhangin g the root flat, showin g sometimes a median aperture near the crown but forms one part with it. A true outer or inner orn amenta rootjuncti on. A shallow less developed media-basal sulcus is ti on is absent. present. The root is elongated and has a more or less rectangul ar ap pearance. From the crown-root juncti on downward , the root is narrowin g and the basal edges are sli ghtly rounded. Two or LOWER JAW three foramina are present at each side of the apron. The in The teeth are strongly compressed and interlocked. The ner face is flat, showing a median aperture near the crown crown base width is approx. 30% less th an its height , and root junction; sometimes a poorly developed median vertical also 30% the root height. The crown is hi gh and symmetri groove is present, which is more distinct on the lateral and call y tri angul ar in the symphyseal teeth but becomes increas posterior teeth . A deep media -basal sulcus is always present. ingly asymmetri cal and less hi gh in lateral and commissural teeth . The crown possesses a relatively well developed LOWER JAW rounded blade at each basal edge, continued upward as a poorfy developed serrati on, which disappears totall y toward The teeth are strongly compressed and interlocked. The the apex. The mesial blade is absent at lateral teeth and those crown base width is equal to its height, but half the root toward the commissure. Both cuttin g edcres are more or less height. straight. ~ "' The crown is high and symmetricall y tri angul ar in the sym The outer face of the crown is convex and a very broad apron physial teeth but becomes increasingly asymmetrical and extends nearly to the root base. The apron is not overhangi ng less hi gh in lateral and commissural teeth. The crown pos the root but forms one part with it. From the crown-root junc sesses a relatively small , bluntly ro unded blade at each basal ti on downward, the apron continues its width and more or edge, continued upward as strong serrati on, which becomes less narrows to half its size ne(\r its lowest part. A shall ow reduced in upper crown half and fi nall y disappears totall y aperture is present at each side of the apron. The basal edges toward the apex. The mesial bl ade diminishes in size on tooth of the root are sli ghtl y rounded. A weak outer mesial depres positi ons toward the commissure. Both cutting edges are sion is also due to in terlocki ng. strongly sigmoid . On the inner face of the crown there is a well developed The outer face of the crown is convex and a broad apron ex tends nearly to the root base. The apron is not overhancr in cr uvula without basal costul es or depression. A large median "' "' aperture is present at each side of the uvul a and one larcre the root but fonm one part with it. From the crown-root junc- median aperture below the uvul a. A short, broad, m e d io-ba~ tion downward, the apron is narrowin g to half its size. A large sal sul cus is present. Two to four foramina surround the sul aperture is present at each side of the apron. Near the junction cus, and several scattered foramina are on the outer basal o f the apron and root, some vertical protuberances are edge of the root. A weak inner di stal depression is due to in present. The basal edges of the root are sli ghtly rounded. A terlocki ng of the lower teeth. weak outer mesial depression is also due to interl ockin g. On the inner face of the crown there is a rectangular uvula at the symphyseal tooth that becomes more oblique and less Oxynotus centrina (LINNAEUS, 1758) developed in teeth toward the commissure. The uvul a LlNNAEUS, 175 8 : Squalus centrina. Systema Naturae. presents a basal depression. A large medi an aperture is Ed. l O( l ) :233. present at each side of the uvula and one large, median aper- · Plates 4 to 6 ture below the basal depress ion. A short, broad, media-basal sulcus is present. Two to fo ur foramina surround the sulcus and several scattered fo ramina are on the outer basal ed cre of This species shows a strong dignathic heterodonty and a . "' weak monognathic heterodonty. The root is always the root. A weak mner distal depression is due to interlockin g anaul acorhi zid . of the lower teeth. The dimensions of the lower teeth are subcentrimetrical, those of the upper teeth plurimilimetri cal in size. 8 J. HERMAN, M . HOVESTADT-EULER & D.C. HOVESTADT
Oxynotus paradoxus FRADE, 1929 width, but half the root height. The symphyseal tooth has a Boletim de Sociedade Portuguesa de Ciencias naturais. symmetrical tri angul ar crown with slightly arched cutting Lisboa. I 0(22) : 263-267, fi g. I. edges. The lateral teeth maintain symmetrical, less high, and Textplates 3, 4 , plates 7 to I 0. nan ower toward the commissure. Both mesial and distal cut ting edges are smooth. This species shows a strong dignathic heterodonty and a The outer face is strongly convex and a broad apron extends weak monognathic heterodonty. The root is always nearly to the root base. The apron is arched at the base and anaul acorhi zid . slightly overhangs the root. A true outer or inner ornamenta The dimensions of the lower teeth are subcentrimetrical, ti on is absent. those of the upper teeth plurimilimetrical in size. The root is elongated and has a more or less rectangular ap pearance with a slight constricti on half way its height. The UPPER JAW root is slightly narrowing at he base and the basal edges are slightly rounded. Foramina are absent at each side of the The teeth are compressed, having a more or less vertically apron. The in ner face is fl at showing a median aperture near elongated crown and root. the crown-root j unction, becoming less developed in lateral The height of the crown is twice. as high as the crown base teeth and disappears near the commissural positions. A deep medi o-basal sulcus is always present.
LOWER JAW
The teeth are strongly compressed and interlocked. The crown base width is equal to its height, but half the root height. The crown is hi gh and symmetrically triangular in the symphyseal teeth but becomes increasingly asymmetrical and Jess high in lateral and commissural teeth. The crown possesses a relatively well developed rounded blade at each basal edge, continued upward as a poorl y developed serra ti on, whi ch disappears totally toward the apex. The mesial bl ade is absent at lateral teeth and those toward the commis sure. Both cutting edges are slightly sigmoid . The outer face of the crown is convex and a broad apron ex Textplate 3 : Oxynotus paradoxus FRADE, 1929. Female tends nearl y to the root base. The apron is not overhanging 920mm t. l., caught off north-west Ireland, 540m the root but fonns one part with it. From the crown-root j unc dept h, Ireland. Outer view of the upper dentition. tion downward, the apron continues its width and more or Magnificati on x6. · Jess narrows to half its size near its lowest part. A shallow
Textplate 4 : Oxynotus paradoxus F RADE, 1929. Female 920mm t.l. , caught off north-west Ireland, 540m depth, Ireland. Diagraph of whole lower left toothset and of the symphyseal tooth (inner side) Magnification x 14. II
Contributions to the odontological study of living Chondrichthyes I 2 9
aperture is present at each side of the apron. The basal edges height of the crown is twice as high as the crown base width, of the root are slightly rounded. A weak outer mesial depres but half the root height in 0. bruniensis, 0. centrina and 0. sion is also due to interlocking. paradOX/IS. On the inner face of the crown there is a uvul a presenting coarse basal costules. A large median aperture is present at LOWER JAW each side of the uvula and one large, median aperture below the uvula. A short, broad, medio-basal sulcus is present. Two The teeth of 0 .centrina's lower j aw possess strongly sig to four foramina surround the sulcus, and several scattered moid cutting edges Character detail Oxynotus bruniensis Oxynotus centrina Oxy11otus paradoxus Species Upper jaw teeth toward commissure oblique No Yes No Upper jaw teeth apron overhangs the root Yes . No Yes Upper jaw teeth cutting edges shape arched No No Yes Upper jaw teeth crown height twice the crown base width, but half the root height Yes Yes Yes Upper teeth apron gradually narrows downwards No Yes No Lower jaw teeth cutting edges shape sigmoid No Yes Yes Lower jaw teeth cutting edges shape straight Yes No No Lower jaw teeth distal blade well developed Yes No Yes Lower jaw teeth serration well developed No Yes No Lower jaw teeth crown base width equals height and half the root height No Yes Yes Lower jaw teeth crown base width 30% less than height and 30% of root height Yes No No Lower jaw teeth apron graduall y narrows downwards No Yes No Lower jaw teeth uvula with basal depression No Yes No Lower jaw teeth uvula with coarse basal costules No No Yes Lower jaw teeth uvula smooth Yes No No Table 1 II 10 J. HERMA N, M. HOVESTADT-EULER & D.C. HOV ESTADT Conclusions CERVIGON F. , 1961 : Una nueva especie de 0 .\)'notus de las costas de Ven ezuela. No vedades Cientifica., Contribuciones ocasionales Although generally the three species share many tooth mor del Museo de Historia Natural La Salle. Serie zoo/ogica. Caracas. phological characters, some significan t differences appear in 27: l-10,4 fi gs. both upper and lower jaw (see table I above). COMPAGNO L.J.V. , 1984 : FAO species catalogue. Vol .4. Sharks of the wo rld . An annotated and illustrated catalogue of shark species 0. centrina shares upper and lower teeth dimensions and know n to date. Part I. Hexanchiformes to Lamniformes. FAAO Fi sheries Synopsis. Rom a. (125). Vol.4. Part I: 24-129 . lower teeth sigmoid shape of the cutting edges with 0. paradox us but none of the characters with 0. bruniensis. FRADE F. , 1929 :. Une nou vell e espece ou un e abe rrati on 0 . paradoxus shares an overh anging apron of the upper teeth individuclle de 1' 0 .\]'IIO WS centrina (L.). Boletim de Sociedade Portuguesa de Ciencias nawrais. Lis boa. I 0(22) : 263-267, fi g. I. and a well developed di stal blade with 0. bruniensis. 0. bruniensis is unique by straight cutting edges and a crown GARRI CK J.A. F. , 1960: Studi es on New Zealand Elas mobranchii . base width 30% less th an its height and 30% of root height in XI. Squal oids of th e genera Deania, Etmoptem s, Oxynotus and Dalatias in New Zealand waters. Transaction of th e royal Society of the lower teeth New Zealand. Wellington. 88(3): 519-557, 6fig. 0 . centrina is unique by possessing lateral and commissural teeth becoming oblique with a graduall y narrowing apron in HERMAN J. , HOV ESTADT-EULER M. & HO VESTADT D., 1989: Con tributi ons to the study of the co mp arati ve morphology of teeth and the upper teeth and an apron gradually narrowing down other releva nt ichth yo dorulites in li ving supraspecific taxa of wards, a uvul a with a basal depression and a well developed Chondri cht ya n fi shes . Part A : Selac hii . N°.3 : Order Squaliformes. serration on the cutting edges in the lower teeth. Families Ec hin orhinidae, Oxynotid ae and Squ ali dae. Bulletin de 0. paradoxus is unique by arch-shaped cutting edges in the I'Institut royal des Sciences naturelles de Belgique. Biologie. upper jaw teeth and a uvul a wi th coarse basal costules in the Bruxe ll es. 59: 101-157. lower teeth. HERMAN J. , HOVESTADT-EULER M. & HOV ESTADT D., 2003: Co n The three species share th e crown height that eq uals root but tributions to the stud y of th e co mp arative morphology of teeth and is half the root height in the upper teeth . oth er releva nt ichthydorulites in li ving supras pecifi c taxa of Chondri chth yan fi shes. Part A : Selac hii . Adde ndum to I : Order Hexanchiformes, 2 : Order Carcharhiniformes, 3 : Order Squali Acknowledements formes Tooth vasc ul ari zation and phylogeneti c interpretati on. Bul letin de 1'/n stiwt royal des Sciences naturelles de Belgique. Authors like to thank Dr. G. Lenglet, Institut royal des Biologie. Bru xe ll es. 73 : 5-26. Sciences Naturell es de Belgique and Dr. M. McGrouther, LAST P.R. & STEVENS J.D. , 1994: Sharks and Rays of Australia. Australi an Museum , Ichthyology Section for givin g access CS IRO di vision of Fi sheri es. Hoba rt . 5 13p., 84p l. to specimens at their di sposal. The SEM photographs were LI NNAEUS K., 1758 : Sys tema Naturae. Ed. ! 0. I :233 . taken by J. Ci lli s (In stitut royal des Sciences naturelles de OGILBY J.D ., 1893 : Desc rip tion of a new shark from the Tas mani an Belgique). coast . Records of th e Australian Museum . Sidney. 2(5) :62-63 . Bibliography BI GE LOW H.B. & SCHROEDER W.C ., 1948: Fi shes of th e Western North Atl anti c. Part. I. Memoirs Search Foundation f or Marin e Re search. New Haven. 576p. HERMAN, J. CADENAT J. & BLACHE J., 198 1 : Requins de Mediterranee et d' Atlantique (plu s parti culi erement de Ia Cote Occidentale IRSNB, Service Geologique de Belgique. Rue Jenner 13 , d' Afrique). Editions de /'Office de Ia Recherche Scientifique et B - I 000 Brussels. Belgium Technique Outre-Me1: Co llection Faune Tropicale. Pari s. 22: 141- E-mail : j .herman @s kynet.be 149. CAS lER E., 196 1 : Transfo rm ati on des systemes de fixatio n et de HOVESTADT-EULER, M . & HOVESTADT, D.C. vascul ari sati on dentaires dans !'evolu tion des selac iens du Sous Merwedelaan 6 Ordre des Squaliformes. Me11wires de /' In stiwt royal des Sciences NL- 4535ET Terneuzen. The Netherl ands naturelles de Belgique. Bruxell es . 2Cinc Serie. 65 : 61p. E-mail : [email protected] n 0 ::l o-s 0 ::l (/> 5 5- (l) 0a. 0 ~ 0 {IQ n !::. (/> ca. '< 0 -... < ::l (/Q 0 0 a.::l cs· ::::- 5- '< (l) (/> -... 1-.J Plate 1: Oxynotus bruniemis (OGILBY, 1893). Male 560mm t.l., caught off Wollongon, New-South-Wales, A ustral ia. Inner view of the same lower left toothsel. loJ ~ :r: m ;;v 3::: )> z 3::: :r: 0 < m {/) ;;;! CJ -;-! m c r m ;;v Ro CJ h :r: 0 < m {/) ;;;! CJ-l Plate 2 : Oxynotus bruniensis (OGILBY, 1893). Male 560mm t.l., caught off Wollongon, New-South-Wales, Australia. Outer and inner views of two upper anterior teeth. n 0 ;:l 5. cr § 0 ;:l V> 0 ~ (1) 00. 0 ;:l 0 0 o_s. n 2. V> c0. '< 0...,., :::. ;:l (JQ n ~ 0 ;:l 0. ~ . n ~ s- '< (1) V> -... 1'-.l Plate 3 : Oxynotus hruniensis (OGILBY, 1893). Male 560mm t.l. , caught ofT Wollongon, New-South-Wales, Australia. Inner and outer views of the three first lower teeth . w ..,. :- :r: rn :N 3::: )> z 3::: :r: 0 < tTl (/) :;; 0 m--l c r tTl :N ~ n0 :r: 0 < rn (/) :;; 0 --l Plate 4: Oxynotus centrina (L INNAEUS, 1758). Female 460mm t.l., caught Cap-cles-Biches, 30m depth, Dakar, Senegal. Diagraph of· the whole lower toothset (inner view). Magnification x 9. () 0 :J ~ :::;. 0" ;:. 0 :J V1 0 :;:. (1) 0 0.. 0 :J £ 0 o.s. n 2. V1 E 0.. '< 0...., ::: :J [fq () :T 0 :J 0....., r;· :T :;:. '< (1) V1 --1--.l Plate 5 : Oxynotus centrina (L INNAEUS, 1758). Female 460m m t.l. , caught Cap-des-Bicl1es, 30m depth, Dakar, Senegal. Outer and inner views of upper parasymphyseal, lateral and commissura l teeth. Magnification x 50. VI 0\ :- ::r: tT1 ::<> 3:: > .z 3:: ::r: 0 < tT1 Vl );! 0..., r, c r tT1 ::<> ?!' 0 0 ::r: 0 < tT1 Vl );! ...,0 Plate 6 : Oxynotus centrina (L INNAEUS, 1758). Female 460mm t.l., caught Cap-des-Bicl1es, 30m depth, Dakar, Senegal. Outer and iner views of symphyseal, third and comm issural lower teeth. Magnification x20. (") 0 ::l :::::. 0"' §. 0 ::l (/l 0 ~ 0 0.. 0 ::l 0 0 r!::. 0 ==- c(/) 0.. '< 0...,., < ::l {fQ (") :::; 0 ::l ,..,0.. c=;· ~ --<: (i> (/l ..__ N Plate 7 : Oxynotus paradoxus FRADE, 1929. Female 920mm t.l. , caught off north-west Ireland, 540m depth, Ireland. Outer and inner views of parasymphyseal, third and fifth upper teeth. -..) 00 ~ ::c tn :Al ~ >z ~ ::c 0 < tn (,/) :;: -i0 mc r tn :Al Ro 0 0 ::c 0 < tn (,/) :;: 0-i Plate 8 : Oxynotus paradoxus FRADE, 1929. Female 920mm t.l. , caught off north- wes t Ireland , 540m depth, Ireland. Outer view of the whole lower toothsel. n 0 ::> CJ ;:;. 0 ::> Vl 8 ::r ('1> 00. 0 ::> 8 0 (IQ 0 !::... Vl E 0. '-< 0...., < ::> (JQ Q 0 ::> ...,0. ()' g: -< ('1> Vl ...... N Plate 9: Oxynotus paradoxus FRADE, 1929. Female 920mm t.l. , caugh t off north-west Ireland, 540m depth , Ireland. Outer view of the lower right teeth (without the symphyseal). \0 1'-.l 0 :- :r: m :;o :s: )> z :s: :r: 0 < m (/) ~ 0 -;-1 m c r m :;o Ro 0 0 :r: 0 < m (/) ~ ~ Plate 10: Oxynotus paradoxus FRADE, 1929. Female 920mm t.l. , caught oil north-west Ireland, 540m depth, Ireland. Inner view of the lower right teeth (without the symphyseal).