865 



Re-identification of a lamnid shark embryo 



Henry F. Mollet 



Moss Ldndicig Marine Laboratories 

 Moss Landing, California 95039 9647 

 E mail address molletiaipacbell.net 



Antonio D. Testi 



Italian Sliark Research Project 

 Via A Solan 43/2 

 20144 Milan, Italy 



Leonard J. V. Compagno 



Shark Research Centre 



PO Box 61 



8000 Cape Town, South Afnca 



Malcolm P. Francis 



National Institute of Water and Atmosphenc Research 

 PO Box 14-901 

 Wellington, New Zealand 



In August 1903. a 400-500 kg preg- 

 nant female lamnid shark was caught 

 in the Strait of Messina, Mediterra- 

 nean Sea. She was reported to contain 

 25-30 embryos, one of which was 

 saved and taken to the local Marine 

 Institute, where it was subsequently 

 examined by Sanzo (1912). The male 

 embryo measured 36.1 cm total length 

 (TL), weighed 800 g, and had a greatly 

 distended abdomen, as is typical of 

 embryos of oophagous lamnoid sharks 

 (Gilmore, 1993). The mother and the 

 remaining embryos were not saved. 

 Because Sanzo was not able to exam- 

 ine the adult female from which the 

 embryo was taken, the embryo was 

 identified by a process of elimina- 

 tion, based mostly on morphometries 

 of postnatal specimens. Sanzo (1912) 

 concluded that the embryo was a 

 white shark, Carcharodon carcharias 

 (Linnaeus, 1758). According to Sanzo 

 (1912), the embryo was requested in 

 1909 by E. Giglioli and was then (in 

 1912) conserved at the Vertebrate 

 Museum of the Superior Institute of 

 Studies in Florence. 



Sanzo's (1912) identification was 

 questioned by many (Tortonese, 1950, 

 1956; Bass et al., 1975; Pratt' ) but 

 was assumed to be correct by Gilmore 



(1993). Tortonese (1950) suggested 

 that the morphometric arguments 

 used by Sanzo (1912) did not rule out 

 the shortfin mako ilsiirus oxyrinchus 

 Rafinesque, 1810) but that the high 

 fecundity of 25-30 was more consis- 

 tent with C. carcharias than with /. 

 oxyrinchus or a Lamna species. A lack 

 of information on lamnid reproduction 

 and the misidentification of a likely 

 Galeorhinus galeiis (Stevens^) with a 

 litter of 30 as Lamna by Neill (1811), 

 may have led Sanzo (1912) to consider 

 the porbeagle Lamna nasus (Bon- 

 naterre, 1788) instead of the shortfin 

 mako as the most likely alternative 

 to the white shark. Shann (1911) had 

 questioned Neill's identification but 

 this was not available to Sanzo (1912). 

 Bass et al. (1975) incorrectly quoted 

 Tortonese (1956) as saying that the 

 embryo could have been a porbeagle. 

 Tortonese (1950) pointed out that 

 Sanzo (1912) mistook the large yolk- 

 filled stomach (due to oophagy) for a 

 yolk sac. Gilmore (1993) reviewed the 

 reproductive biology of lamnoid sharks 

 and included a redrawn sketch of the 

 Sanzo (1912) embryo, still identified 

 as a white shark, and also incorrectly 

 stated that Sanzo (1912) had docu- 

 mented oophagy for the white shark. 



Francis ( 1996) reviewed lamnid fecun- 

 dity data and showed that the shortfin 

 mako has the highest known fecundity 

 (18 embryos; Branstetter, 1981) in the 

 order Lamniformes, which suggested 

 to us that the embryo was more likely 

 a shortfin mako. 



Sanzo's ( 1912) embryo, well preserved 

 in 75% ethanol, was photographed by 

 Storai'* in the Species Museum "La 

 Specola" (MZUF 5911) in Florence in 

 1992 (Mojetta et al., 1997). The photo- 

 graph — in color — suggested to us that 

 the lost embryo had been found. This 

 presented an opportunity for re-exam- 

 ining the embryo and checking Sanzo's 

 identification. 



The correct identification of the San- 

 zo embryo is important to our under- 

 standing of lamnid reproduction and 

 possibly white shark conservation. Few 

 pregnant female white sharks or em- 

 bryos have been reported, and little 

 is known about litter size, gestation 

 period, or the timing and duration of 

 the reproductive cycle (Uchida et al., 

 1987, 1996; Francis, 1996; Mollet et 

 al., 2000). Such information is vital for 

 understanding the population dynam- 

 ics of the white shark, which is now 

 regarded as a threatened species (Com- 

 pagno et al., 1997). If the Sanzo embryo 

 were a white shark, then it would be 

 the smallest white shark embryo ever 

 reported. Most have been greater than 

 100 cm TL ( Francis, 1996; Uchida et al., 

 1996), although Bigelow and Schroeder 

 (1948) reported white shark embryos 

 in the range 20-61.6 cm TL, without 

 giving any details. A white shark litter 

 with embryos of 61 cm TL (5.4 kg each, 

 Ellis and McCosker, 1991) was caught 

 in the Mediterranean Sea (Norman 

 and Eraser, 1938). No description of the 

 embryos was given; however, the mass 

 of the embryo suggested that it had a 



' Pratt, H. L. 1996. Personal commun. 

 Narragansett Laboratory, National Ma- 

 rine Fisheries Service, 28 Tarzwell Drive, 

 Narragansett RI 02882. 



•^ Stevens, J. D. 1998. Personal commun. 

 CSIRO Marine Research, P O. Box 1,538, 

 Hobart, Tasmania 7001, Australia. 



■^ Storai, T. 1992. Personal commun. Mu- 

 seum of Natural Science of Valdinievole. 

 Piazza L. da Vinci 1, Pescia PT Italy. 



Manuscript accepted 24 May 2002. 

 Fish. Bull. 100;86.5-87,5 (2002). 



