Van Winkle-Palmer (1958:169) stated that no holotype was found, and no other original material than those specimens present in the University of California is known.
Carpenter (1864:610) mentions: "Other series, though not so complete, have since been received in safety; and through the liberality of the Californian Survey and of the Smithsonian Institution, as well as through the energy and kindness of Dr. Cooper, they are already being distributed to the Cumingian Collection, the British Museum, the museums at Cambridge, Mass., Philadelphia, Albany, Montreal, &c., as well as to the collections of working naturalists."
Recently, a glass tablet holding a specimen of T. cooperi was detected in the General Collection at NHMUK by the present editor, which has been donated to the Museum by the Smithsonian in 1865 (information taken from the Registration book at NHMUK 02/05/2014). As the locality on the card is the same as the type locality mentioned in the original description (San Pedro), this sample (NHMUK Reg No 18188.8.131.52) could be considered a syntype. Confirmation through examination of documentation of the gift is to follow shortly.