TASMANITES 

 GENERA OF FOSSIL SPORES 



11 



Genus Tasmanites Newton, 1875 



Sporangites Dawson, 1863 (pars.), Canadian 

 Naturalist, New Ser. vol. 8, no. 6, pp. 431-457. 



Plate 1, figure 1 



General Discussion. — There is a group 

 of highly distinctive fossil spore-like 

 bodies which occur most notably in the 

 Devonian-Mississippian black shale that 

 requires a name amenable to standard 

 taxonomic usages. At first, it was sup- 

 posed that the name Sporangites, if sup- 

 ported by an emended definition, could 

 apply. We are now of the opinion that 

 the application of that name is not correct 

 in this connection, and that the various 

 descriptions that have appeared for Spo- 

 rangites are so highly conflicting and 

 ambiguous or erroneous that that particu- 

 lar name should be considered a nomen 

 ambiguum. This is herewith proposed in 

 view of the difficult taxonomic situation 

 as detailed below. 



The present most common use of the 

 term ''Sporangites'' is by geologists who 

 wish to record the presence of more or 

 less disc-shaped, resinous-appearing bodies 

 that are very commonly found in the 

 Devonian-Mississippian black shale, many, 

 but by no means all, of which are properly 

 referable to Tasmanites as given below. 

 This common usage does not conform to 

 the original application of the name and 

 is so noncritical and general in application 

 that it would probably be unwise to at- 

 tempt to restrict it even if this could be 

 done in accordance with taxonomic pro- 

 cedure. Possibly no one, certainly not its 

 author, has used the term with taxonomic 

 consistency and practically all records of 

 Sporangites must merely be regarded as 

 indicative of some small rounded, brown- 

 ish or yellowish bodies. Needless to say, 

 many kinds of plant microfossils cor- 

 respond to this characterization. How- 

 ever, there is no reason why "sporangites" 

 may not be continued to be used in this 

 sense, since it serves a descriptive pur- 

 pose, in spite of the fact that it is botanical- 

 ly misleading; but the name should not 

 be italicized or treated as a generic desig- 

 nation. 



Sporangites was first proposed by 

 Dawson in 1863 (p. 454). Here he 



applied the name to spores or "spore 

 cases" which he thought were referable 

 to Lepidodendron, Calamites and similar 

 plants. Sporangites papillata, about one 

 inch (!) in diameter, and 6". glabra about 

 the size of a mustard seed, were men- 

 tioned ; later this description was repeated, 

 accompanied by small diagrams (Dawson, 

 1865, p. 165, pi. 12, figs. 80-81). These 

 fossils were associated with coal at Jog- 

 gins, Nova Scotia, and may in part have 

 been material that would be placed now 

 with Triletes, but there is no way to con- 

 firm this from his description or illustra- 

 tions. His repeated descriptions of 5^. 

 papillata as "one inch in diameter" leads 

 one to suspect it may have been a seed. 

 In 1871 (a, b) Dawson described an 

 additional species from the black shale at 

 Kettle Point on Lake Huron as S. huron- 

 ensis; "small globular papillate spore- 

 cases — probably of some Lepidodendroid 

 plant." Later in the same year (Dawson, 

 1871c) he also referred a specimen con- 

 sisting of a small whorl of leaves or bracts, 

 first described as Annularia acuminata, to 

 Sporangites. This last interpretation of 

 Sporangites was accepted by Slopes 

 (1914). Forms similar, in general, to 

 those from Kettle Point are usually con- 

 strued as Sporangites by present day 

 geologists, but it seems evident that neither 

 of these interpretations corresponds at 

 all closely with Dawson's first generic 

 application of the name. 



Dawson in 1883 presented a report on 

 "Rhizocarps in the Paleozoic Period" at 

 the meeting of the American Association 

 in Minneapolis, an abstract of which ap- 

 peared in the American Association for 

 the Advancement of Science proceedings 

 (1884a). The entire paper also appeared 

 in the Canadian Record of Science for the 

 same year (1884b). The essential des- 

 criptive part and the figures are identical 

 in both. Here Dawson proposed the name 

 Protosalvinia including two species given 

 as ''Sporangites (Protosalvania) hrazilien- 

 sis U.S.," and "S. (P.) hilohatus n.s." 

 Dawson stated that if we compare the 

 separate macrospores of the Brazilian 

 sporocarps, and especially those which are 

 found detached from their envelopes 

 (Sic!) with Sporangites hitronensis, we 



