Regular Paleontological Publications

Papers with an explicit taxonomic or phylogenetic section (i.e., with a taxonomic list, a taxonomic treatment, or a new taxon name) have been counted for the period of publication studied (Tablel.1). Counting only such papers reduces the sample to those more or less linked to a phylogenetic perspective; 3,031 publications devoted to various taxa, and with an explicit taxonomic section, have been published for the period studied and the journals analyzed. Among them, 440 have a cladistic section (a cladistic section is recognized here if a cladogram or equivalent parenthetic notation appears in the publication, even if it is not based on a parsimony analysis). The relative cladistic contribution is thus 14.5% (number of papers with cladistic section divided by number of papers with explicit taxonomic section).

Fluctuations in taxonomic and cladistic publications over time are quite different (Fig. 1.1). In both cases, we note an increase in the number of publications. This was tested using Spearman's nonparametric Rank Correlation Test (Table 1.2) (see Swan and Sandilands, 1995), the equivalent of Pearson's Classic Correlation Test but applied to not normally distributed variables, which is the case here. Results indicate that both taxonomic and cladistic publications increase in number over time. However, the increase in the number of cladistic publications is clearly much more marked (Fig. 1.1). A second test was performed on the percentage of cladistic publications to test for the net increase in the cladistic approach (to eliminate the increase in cladistic

Table 1.1 Number of publications in regular paleontological literature (1985-2003). "Taxonomy" refers to publications with an explicit taxonomic section, "Cladistics" to publications with a cladogram (or a parenthetic notation) constructed with or without parsimony analysis (see text).

Table 1.1 Number of publications in regular paleontological literature (1985-2003). "Taxonomy" refers to publications with an explicit taxonomic section, "Cladistics" to publications with a cladogram (or a parenthetic notation) constructed with or without parsimony analysis (see text).

Title

Taxonomy

Cladistics (%)

Geobios

575

36 (6.26)

Journal of Paleontology

1,501

154 (10.26)

Lethaia

112

41 (36.61)

Palaeontology

741

140 (18.89)

Paleobiology

102

69 (67.65)

Total

3,031

440 (14.52)

Fig. 1.1 Number of publications over time from five regular paleontological journals (see text).

Table 1.2 Nonparametric Spearman's Rank Correlation Test for various data sets (see text). rs: Spearman's Rank Correlation Coefficient, NS: test nonsignificant, *: test significant at 95% confidence level, **: at 99% confidence level, ***: at 99.9% confidence level. Results are given with ex-aequo correction (see Swan and Sandilands, 1995).

Table 1.2 Nonparametric Spearman's Rank Correlation Test for various data sets (see text). rs: Spearman's Rank Correlation Coefficient, NS: test nonsignificant, *: test significant at 95% confidence level, **: at 99% confidence level, ***: at 99.9% confidence level. Results are given with ex-aequo correction (see Swan and Sandilands, 1995).

r s

p-values

Year, Number of Taxonomic publications

0.60

0.011

*

Year, Number of Cladistic publications

0.93

<0.0001

***

Year, Percentage of Cladistic publications

0.94

<0.0001

***

publications due to the increase in the total number of publications). Results indicate that the cladistic approach is increasingly used in paleontology (Table 1.2).

To explore phylogenetic practices in detail, each of the 3,031 previous papers is attributed to the taxon with which it deals. Here, 12 major taxonomic entities are recognized: plants, corals and relatives, sponges and relatives, trilobites, arthropods (excluding trilobites), brachiopods and bryozoans, bivalves, gastropods, cephalo-pods, echinoderms, graptolites, and finally vertebrates. They may not correspond to identical taxonomic levels, yet each of them reflects a particular bauplan organization, reserved for a particular community of scholars. Results reflect the domination of the vertebrate community in the number of papers with taxonomic purpose published (Fig. 1.2A). The pecking order is then brachiopods and bryozoans, arthropods (excluding trilobites), echinoderms, and cephalopods in fifth rank, just before trilobites. In contrast, the situation is quite different for papers with cladistic purpose (Fig. 1.2A). Vertebrates are still dominant, but the ranking of other groups has drastically changed: second are echinoderms, then trilobites, brachiopods and bryozoans, and arthropods (except trilobites) in fifth position. Cephalopods are only ranked in eighth position, after other mollusk representatives (gastropods and bivalves, respectively). The proportion of cladistic papers per major taxonomic

Fig. 1.2 Comparative number of publications for twelve higher-level groupings (not of equal rank), over time, in five regular paleontological journals (see text). A: number of papers; B: percentage of cladistics papers.

entity demonstrates the dramatic underuse of cladistics within the fossil cephalopod community (Fig. 1.2B). The ratio is less than 5%, and only sponges and relatives and plants get lower scores. The percentage of cladistic publications for fossil cephalopods varies from one journal to another (Table 1.3; see Appendix for detailed bibliographic references).

Table 1.3 Number of publications for cephalopods only, in regular paleon-tological literature (1985-2003). "Taxonomy" refers to publications with an explicit taxonomic section, "Cladistics" to publications with a cladogram (or parenthetic notation) constructed with or without parsimony analysis (see text and Appendix).

Table 1.3 Number of publications for cephalopods only, in regular paleon-tological literature (1985-2003). "Taxonomy" refers to publications with an explicit taxonomic section, "Cladistics" to publications with a cladogram (or parenthetic notation) constructed with or without parsimony analysis (see text and Appendix).

Title

Taxonomy

Cladistics (%)

Geobios

60

1 (1.67)

Journal of Paleontology

81

2 (2.47)

Lethaia

7

2 (28.6O)

Palaeontology

56

3 (5.36)

Paleobiology

2

2 (1OO)

Total

206

10 (4.85)

Results for fossil cephalopods are very different from those for all taxa as a whole. In Fig. 1.3, there is quite clearly a negative correlation for the number of taxonomic papers, and no correlation for the number of cladistic papers. These observations are confirmed using Spearman's Rank Correlation Test (Table 1.4).

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