Replace Dendroplex by the newly described name Paludicolaptes for D. picus and D. kienerii.

Proposal (1004) to South American Classification Committee

Replace Dendroplex by the newly described name Paludicolaptes for D. picus and D. kienerii.

Since the acceptance of proposal 316, we use the genus Dendroplex for the woodcreepers D. picus and D. kienerii. More recently, however, Raposo et al. (2018) asserted that Dendroplex is a junior synonym of Xiphorhynchus and introduced a new generic name, Paludicolaptes, for picus and kienerii.

Background: The background in Proposal 316 by Aleixo provides the basic information needed for understanding this case:

“Since 1951, authors (Peters 1951, Clements 2000, Marantz et al. 2003, Dickinson 2003) have placed the Straight-billed (X. picus) and Zimmer's (X. kienerii) woodcreepers in the genus Xiphorhynchus, even though earlier authors classified them in the genus Dendroplex (Sclater 1890, Hellmayr 1925, Zimmer 1934, Todd 1948). The original characterization of Dendroplex (1827: 354) provided only a brief diagnosis of the new taxon, and no reference to a type species. Ten years later, the same author (Swainson 1837: 313-314) provided essentially the same diagnosis of the original description, but this time it was accompanied by an illustration showing the straight culmen and lateral compression of the type species. However, at the end of the characterization, Swainson added: "The scansorial type D. guttatus Spix i, 91, f. 1", which refers to figure 1 of plate 91 in Spix (1824), thereby satisfying the requirements of ICZN for type species designation by subsequent monotypy (ICZN 1999). Subsequently, Hellmayr (1925: 288) pointed out that Swainson's diagnoses of 1827 and 1837 and bill outline correspond to the characters of the Straight-billed Woodcreeper (originally described as Oriolus picus), although the only species mentioned (D. guttatus Spix i, 91, f. 1), "belongs to the genus Xiphorhynchus Swainson". Following Hellmayr (1925), Peters (1951: 36) recognized that "D. guttatus Spix i, 91, f. 1" depicts in fact a bird now known as Xiphorhynchus ocellatus (Spix 1824), and stressed that under Opinion 65 (Schenk & McMasters 1948: 54) the case of misidentification had to be formally presented to the ICZN for ruling, and that until a decision was reached, Xiphorhynchus ocellatus ocellatus = Dendrocolaptes ocellatus Spix 1824 continued to be the type of Dendroplex.”

“Because the latest (fourth) edition of the International Code of Zoological Nomenclature (ICZN 1999) now allows a misidentified type species to be set aside without the requirement of a ruling from the Commission, Aleixo et al. (2007) proposed the conservation of Dendroplex Swainson, 1827, as a valid taxon.” (Alex Aleixo, October 2007).

New information: Raposo et al. (2018) argued that the type of Dendroplex is Xiphorhynchus guttatus Spix. Their main argument rests on some conceptual aspects of the ICZN. In a nutshell, they argue that because types in the Genus category are nominal (not physical specimens like the types in the species category), the mentioning of Dendrocolaptes ocellatus Spix, 1824 prevails over an illustration of a specimen. Because D. picus was never mentioned in the description, it cannot be the type species of Dendroplex.

ANALYSIS: My reading of The Code suggests that Raposo et al. (2018) adopted an unorthodox interpretation of The Code. The Code says that types in the genus category are “nominal species” (Art. 67.1). But a “nominal taxon,” according to the ICZN Glossary, is a taxon denoted by an available name (as opposed to a taxon without a formal name, e.g. an unnamed clade). Therefore, types in the genus category are “nominal” in the sense that they are denoted by available names, but they are indeed taxa, thus “groups of organisms” (see ICZN Glossary). Therefore, the interpretation by Raposo et al. that such types are “nominal” in the sense that the name itself defines the type, is incorrect; the type is a taxon, and a taxon is a biological entity, not just a name.

In addition, the article that deals with misidentifications of types for the Genus category makes clear that either names or taxa can be used as basis for fixing type species subsequently:

“70.3. Misidentified type species. If an author discovers that a type species was misidentified …, the author may select, and thereby fix as type species, the species that will, in his or her judgment, best serve stability and universality, either

70.3.1. the nominal species previously cited as type species [Arts. 68, 69], or

70.3.2. the taxonomic species actually involved in the misidentification. ....”

In this case the “nominal species previously cited as type species” would be D. guttatus and the taxonomic species actually involved in the misidentification, revealed by the illustration, would be D. picus. Therefore, the choosing of D. picus as type of Dendroplex by Aleixo et al. (2007) is totally compatible with ICZN rules. The fact that D. picus is not explicitly mentioned by Swainson is immaterial.

Recommendation: I recommend voting NO to this proposal. Taxonomic issues aside, the generic name we are currently using for these two dendrocolaptids is correct, as D. picus was validly established as the type species of Dendroplex by Aleixo et al. (2007).

Literature cited:

Aleixo, A., S. M. S. Gregory & J. Penhallurick. 2007. Fixation of the type species and revalidation of the genus Dendroplex Swainson, 1827 (Dendrocolaptidae). Bull. B. O. C. 127: 242-246.

Raposo, M. A., A. Dubois, G. M. Kirwan, C. P. De Assis, E. Höfling, R. Stopiglia. 2018. Synonymization of the genus nomen Dendroplex Swainson, 1827 and description of a new genus of woodcreeper (Aves: Passeriformes: Dendrocolaptidae) with remarks on Articles 67.5 and 70.3 of the Code. Zootaxa 4532(4):561-566.

Santiago Claramunt, June 2024

_______________________________________________________________________________________________________________________________________________

Comments from Areta: “The question here seems to depend on what one understands to be "70.3.2. the taxonomic species actually involved in the misidentification." Raposo et al. (2018) discussed this and consider this taxonomic species to be X. ocellatus, while Aleixo 2007 and Santiago here understand that this taxonomic species would be D. picus. I would say that there are two misidentifications here, and that therefore perhaps this article does not apply in full! It is clear that, based on the diagnosis, Swainson (who is also the author of the genus Xiphorhynchus!) was referring Dendroplex to a species with a straight culmen, and his subsequent designation of D. guttatus = X. ocellatus as type crashes frontally with his diagnosis and the illustration provided (at that time, D. guttatus = X. ocellatus was often considered to be the same as D. picus). I know that The Code is a tool to avoid guessing what people might have been thinking about and attaching strict values to what people "did". Here, "doing" is most the time writing, but when there are contradictions such as the ones in this case, in which a species (X. ocellatus) is ex post facto considered to have been designated as type species when it does not match the illustration AND the diagnosis, I feel the obligation of not assuming that Swainson was thinking on X. guttatus or X. ocellatus as representatives of Dendroplex. What I mean by all this, is that I think that Swainson knew what he was doing (i.e., confronted with specimens he would have unambiguously pointed out picus as "type" of Dendroplex), and that following The Code in the strictest sense and applying rules and concepts retroactively, may make Swainson look incoherent. This rambling may be inconsequential from the perspective of The Code, but I think it is relevant in an attempt to try to understand what happens when we look backwards from the present interpreting what others wrote under a set of rules that were not theirs.

“Curtis Marantz´s second comment is interesting to read and is pretty much aligned with what Raposo et al. (2018) did although for somewhat different, less Code-related reasons: "Secondly, I have looked into the nomenclatural issues discussed by Aleixo et al. (2007) and must admit that they are most complex. It indeed appears that Swainson (1837) erred when he chose D. guttatus as the type for Dendroplex despite the fact that his figure 281e indeed depicts X. picus and only X. picus. Although I am far from an expert on nomenclatural issues I would think that common sense would dictate that, if at all possible, the best course of action to take, if indeed the recognition a separate genus is warranted, may be to abandon the name Dendroplex altogether and propose a new name. This would seem reasonable given not only the confused past surrounding Dendroplex but also because the bill characters first used by Swainson to diagnose Dendroplex do not really apply to kieneri, which has a somewhat different bill shape."

“I would like to see what others think before voting.”

Comments from Robbins: “NO. This is confusing and there appear to be assumptions that may or may not be correct. Seems best to stick with Dendroplex.”

Comments from Jaramillo: “NO”

Comments from Stiles: “YES. An interesting case, with two competing options. A) accept Swainson’s identification of the type specimen of Dendroplex as Xiphorhynchus ocellatus, thus making Dendroplex a synonym of Xiphorhynchus and requiring a new generic name for its two species (= Paludicolaptes?); B) disallow Swainson’s identification as incorrect, substituting kieneri for X. ocellatus and thereby retaining Dendroplex, which is definitely more convenient – but ignores the historical angle: at least to my eye, the plate figure given by Swainson does indeed look like X. ocellatus. I note that in another similar case (the description of coeruleogularis over Uranomitra, accepting Gray’s synonymization of Reichenbach´s and Bonaparte’s generic names for the same group of species - with solid historical backing) in favor of retaining Uranomitra (as causing less inconvenience to current usage), SACC in effect established a precedent more in line with alternative B in the present case. So if we were to be consistent with this precedent, SACC should accept Dendroplex. Needless to say, I disagree.”

Comments from Vitor Piacentini (whose has Remsen’s vote on issues of nomenclature:

“NO. Santiago is correct in his rationale regarding the application of art. 70.3. As such, if the type fixation of Dendroplex relies on the identity of “Dendrocolaptes guttatus Spix (sensu Swainson, 1837)”, I agree the type would have been correctly fixed as [Oriolus] picus Gmelin (= Dendroplex picus) by Aleixo et al. (2007). The allegation by Raposo et al. that type species are purely nominal does not find support in the ICZN at all: if type species were merely nominal, then conceptually there could be no misidentification at all! All the articles of the ICZN dealing with misidentification of type species would be a non-sensical aberration. How do we actually know that a name has been wrongly applied through misidentification? Checking either the specimen involved or relying on a textual description of a morphological feature derived from a specimen (representing a taxon).

“But I must say that, before discussing art. 70.3 and the identity of “D. guttatus Spix (sensu Swainson, 1837)”, one should be sure when Swainson first included a nominal species under Dendroplex, as this define the “first species originally included”, which are the ones candidate to be type species. Only a species cited by an available name may be an originally included species. Swainson (1830) first mentioned that the type of his Dendroplex was “Le Galapiot”, and for that reason Raposo et al. dismissed it as a valid type fixation, and this seem to be correct based on a quick reading of the rules. However, when Swainson refered “351. le Galapiot”, he was actually indicating a species account in a previous work [in Griffith et al. 1829], which entry is entitled “Le Galapiot” and explicitly identifies it as a nominal species (Oriolus picus). In other words, Swainson’s mention of “le Galapiot” is a bibliographic reference rather than a purely taxonomic reference (by a vernacular name). Many bibliographic indications in taxa descriptions also bring an associated vernacular name, but are deemed as valid. It is clear from the publications that Swainson had O. picus as the type of his genus. But, as I said, the Code does not say anything about using bibliographic indication to fix a type species. Can the bibliographic reference of Swainson towards a species account where a nominal species is explicitly identified and cited be accepted as a first inclusion? I think it should, but only the Commissioners can answer that. In any event, even if this inclusion by Swainson himself is not accepted, the type species of Dendroplex would have been correctly fixed by Aleixo et al. 2007 as Oriolus picus, in my view, and so Dendroplex is a senior synonym of Paludicolaptes.

“For the record, here is the comment on the case that we have included in our last version of the Brazilian checklist (Pacheco et al. 2021):

‘Raposo et al. (2018) proposed the new genus Paludicolaptes. They used an article of ICZN (1999) on new taxa description (12.3) to invalidate Swainson's fixation of the type specimen of Dendroplex based on bibliographic indication. However, ICZN (1999) articles that regulate the fixation of type species (66 to 70) are silent on this subject. The case is being submitted to the ICZN for arbitration. Until a final position is available, the traditional treatment (see Aleixo et al. 2007) is maintained here in favor of stability, a basic precept of zoological nomenclature.’ ”

Comments from Lane: “NO. To be honest, I am utterly confused by the original proposal, and this was worsened by Nacho’s and Gary’s comments. So, in the proposal, the idea is that Swainson named Xiphorhynchus guttatus as the type by name, but using an illustration of a bird that was another taxon, which, according to Aleixo et al (2007) Hellmayr helpfully suggested was actually X. ocellatus. Then, Gary mentioned “kienerii,” but again, that species was only mentioned in Aleixo et al. in the context of being the sister to [X.] picus, so I am not sure why he brings up the name here? Finally, Nacho alluded to comments by Curtis Marantz, but I’m not clear which comments those are (perhaps from email exchanges that were not included in the proposal?). Unless there is more to unravel here, I will assume that the Aleixo et al. paper followed the Code sufficiently well that Dendroplex has been satisfactorily fixed to refer to [X.] picus thanks to the diagnostic bill structure. So, unless someone can clarify my several points of confusion above, I will say I feel it best to stick with Dendroplex as the correct genus for the picus-kienerii species pair, so NO to adopting Paludicolaptes as a novel genus for that pair.”

Comments from Steven Gregory (voting for Bonaccorso): “I write to support Vitor Piacentini and vote NO. The authors of the paper "Fixation of the type species and revalidation of the genus Dendroplex Swainson, 1827 (Dendrocolaptidae)." (2007), which included myself, sought to maintain the traditionally accepted position following Hellmayr (1925: 288) that Oriolus picus J.F. Gmelin, 1788 was the type species of Dendroplex Swainson, 1827. The 'misidentification' seems to have arisen from Lesson (1830: 313) where he placed "Oriolus picus, Gm; Gracula picoides, Shaw; Enl. 605" in the synonymy of "Dendrocolaptes guttatus, Spix, pl. 91." Looking at Spix's plate and comparing it to Enl. 605 (La Talapiot de cayenne) the bill is only vaguely 'similar' in shape and certainly the wrong colour. At the time (BHL had barely launched) we were probably unaware that Swainson himself had commented on the identity of the type species, Swainson in Griffith (1830: 689) "351. Le Galapiot. We omitted to cite this as the type of our subgenus, Dendroplex. (Zool. Journ. 10, p. 354.)" which serves to strengthen the case for misidentification. Following extensive correspondence with several ICZN commissioners we have be told that under no circumstances can vernacular names be 'available' and cannot be cited as the type species of generic names as they are excluded from being an indication by Opinion 1 (ICZN, 1907) and Article 12.3 (ICZN, 1999), so Swainson's remark cannot stand as a designation, and I wonder why he persisted in conflating the two taxonomic species as late as his 'Natural history and classification of birds' (1837: 314), we will never know. I must therefore stand by what I, and my co-authors, wrote (2007) that the bill outlines (1837: 313, fig. 281e) can only refer to the peculiar bill shape of Oriolus picus J.F. Gmelin, 1788, and that the type species should be fixed (under Article 70.3 of the Code) as Oriolus picus J.F. Gmelin, 1788, misidentified as 'D. guttatus Spix, 1824' = Xiphorhynchus ocellatus (Spix, 1824) by Swainson (1837: 314). We only mentioned Dendroplex kienerii (Des Murs, 1856) as being a congener of Dendroplex picus (J.F. Gmelin, 1788), as being the two members of the same clade identified by Marantz et al. (2003).

“There is no 'case law' in Zoological Nomenclature (ICZN, 1999: Introduction, XX) "problems in nomenclature are decided by applying the Code directly, and never by reference to precedent.” I would suggest that the 'considerable confusion' alluded to in Raposo et al. (2018) is entirely of their own manufacture. They attempted to exclude the evidence in Swainson (1837) and insisted that name alone, i.e., a bare "D. guttatus Spix" is all that can be used, but how can it be that "an author discovers that a type species was misidentified" (Article 70.3) without recourse to such evidence? Such an interpretation would make Article 70.3 all but impossible to implement. Although no longer a requirement, and seeing as the type species of Dendroplex has been "long known", even if not to Raposo et al., it may be necessary to apply to the ICZN for a ruling.”

Additional comment from Remsen: Just published today, 30 July 2024, a paper by Steve Gregory emphasizing that a vernacular name cannot be used for a type species: Gregory et al. “The trouble with Myrmornis Hermann, 1783 and Myrmornithinae Sundevall, 1872”, Avian Systematics 2024 2 (VI): N33–N53.

Additional comments from Stiles: “I was evidently confused the first time around. Now Im somewhat less confused -- or at least, I think I understand the alternatives better. So- NO, at least pending an ICZN commission ruling.”