Part 10

From his studies of certain features of the bony palate Tordoff (1954:25-26, 32) concludes that the richmondenines, the emberizines, and the tanagers have a common origin and places these groups in the Family Fringillidae. He excludes the carduelines from this assemblage, suggests that they are closely related to the estrildines, and includes them as the Subfamily Carduelinae in the Family Ploceidae.

In this paper I have presented data obtained from the study of certain features of morphology and biochemistry which I think are less subject to the influence of environmental factors than those features studied by recent workers. It is significant that the data obtained by use of serological techniques and those obtained from the study of leg-musculature point to the same conclusions. On the basis of these data I have drawn several conclusions concerning the relationships of the groups which I studied.

The richmondenines, emberizines, and tanagers are closely related and should be included in a single family, Fringillidae. The Carduelinae and the Estrildinae are closely related subfamilies. Although most recent classifications place the Estrildinae and Passerinae in the Family Ploceidae, the serological evidence indicates that these groups are not closely related. Beecher (1953:303-304) drew the same conclusion from his study of jaw-musculature (see above). I suggest, therefore, that the Carduelinae and the Estrildinae be placed in a family separate from the Ploceidae and that the name Carduelidae (rather than Estrildidae) be used for this group. At present, neither is an accepted family name. Because Carduelis Brisson 1760 is an older name than Estrilda Swainson 1827 and because Carduelis seems to be a centrally located genus in the family, I have chosen the former (although the International Rules of Zoological Nomenclature do not specify that priority must apply in forming family names).

I have been unable to study any of the species included in the subfamilies Fringillinae (not Fringillinae of Tordoff, see 1954:23-24, and below) and Geospizinae of recent classifications; thus these groups have not been discussed above. Beecher (1953:307-308) includes Fringilla in the Subfamily Carduelinae; he includes the geospizines in a separate family, Geospizidae, and states that they are derived from the emberizines. Tordoff (1954:23-24) found that in features of the bony palate Fringilla and the geospizines resemble the emberizines and, on this basis, includes them in the Subfamily Fringillinae.

The Dickcissel, Spiza americana, possesses certain features which merit special discussion. Beecher (1951a:431; 1953:309), on the basis of jaw-musculature, considers it an icterid. To be sure Spiza is in many ways an aberrant member of the group to which it is now assigned (Subfamily Richmondeninae). Spiza, serologically, is closely related to all species of the richmondenine-emberizine-thraupid assemblage. Within this assemblage its nearest relatives are the richmondenines. Spiza differs from the other richmondenines studied and resembles the emberizines and tanagers in the possession of the muscular band which extends from the pars interna of the m. gastrocnemius around the front of the knee. This band, in Spiza, is smaller, however, than in any of the other species. No icterid dissected possesses such a structure. Tordoff (1954:29) states that Spiza is typically richmondenine in palatal structure and makes the suggestion, with which I agree, that Spiza is a richmondenine and may be closely related to the ancestral stock which gave rise to the fringillid assemblage. The serological position of Spiza, approximately equidistant from the other fringillids (Figs. 22, 23), and the presence of the small muscular band around the front of the knee constitute evidence supporting the central position of Spiza.

After consideration of evidence from the studies of external morphology, ethology, myology, osteology, and serology, I propose here an arrangement of the groups which I have studied and submit for comparison the arrangements (of these groups) proposed by Beecher and Tordoff. The names of subfamilies that I have been unable to study are included in my classification and are placed in brackets.

------------------------+----------------------+----------------------- | Proposed by Tordoff | Proposed by Beecher Here proposed: | (1954) on the basis | (1953) on the basis | of the bony palate: | of jaw-musculature: ========================+======================+======================= FAMILY PLOCEIDAE | FAMILY PLOCEIDAE | FAMILY PLOCEIDAE | | [Subf. Bubalornithinae] |Subf. Bubalornithinae | | | Subfamily Passerinae: |Subfamily Passerinae | Subfamily Passerinae distinguished from the | | Estrildinae by patterns | | of jaw-musculature | | (Beecher, 1953:303-304) | | and on the basis of | | comparative serology of | | saline-soluble proteins.| | | | [Subfamily Ploceinae] |Subfamily Ploceinae | Subfamily Ploceinae | | [Subfamily Viduinae] |Subfamily Viduinae | Subfamily Viduinae | | FAMILY CARDUELIDAE | | | | Subfamily Estrildinae: |Subfamily Estrildinae | FAMILY ESTRILDIDAE similar to the | | Carduelinae in features | | of the bony palate and | | habits (Tordoff, 1954: | | 18-22) and in patterns | | of leg-musculature and | | comparative serology | | of saline-soluble | | proteins. | | | | Subfamily Carduelinae: |Subfamily Carduelinae | [In Thraupidae below] distinguished from the | | Fringillidae by features| | of the palate, | | geographic distribution,| | migration patterns, and | | habits (Tordoff, 1954: | | 14-18) and by patterns | | of leg-musculature and | | comparative serology | | of saline-soluble | | proteins. | | | | FAMILY FRINGILLIDAE: all| FAMILY FRINGILLIDAE | FAMILY PARULIDAE members of this family | | Subfamily Parulinae show similarities in | | Subfamily Emberizinae features of the bony | | palate (Tordoff, 1954: | | 22-23), patterns of | | leg-musculature, and | | in comparative serology | | of saline-soluble | | proteins. | | FAMILY THRAUPIDAE | | Subf. Richmondeninae |Subf. Richmondeninae | Subfamily | | Pyrrhuloxiinae | | Subfamily Thraupinae |Subfamily Thraupinae | Subfamily Thraupinae | | Subfamily Emberizinae |Subfamily Fringillinae| [In Parulidae above] |(including Emberizinae| [Subfamily Fringillinae]| and Geospizinae) | Subfamily Carduelinae | | [Subfamily Geospizinae] | | ------------------------+----------------------+-----------------------

SUMMARY

It has long been recognized that the Family Fringillidae includes some dissimilar groups. Specifically, the relationships of the subfamilies Richmondeninae, Emberizinae, and Carduelinae of the Family Fringillidae are poorly understood. Data from two recent studies, one on patterns of jaw-musculature and the other on features of the bony palate, emphasize the dissimilarity of these subfamilies but have given rise to conflicting concepts of the relationships of subfamilies within the Family.

This paper reports the results of studies involving morphological and biochemical features that I consider less sensitive to external environmental factors than are features which have been studied previously. Patterns of leg-musculature were chosen for study because earlier work showed that muscle patterns in the legs of passerine birds are highly stable and vary but little. Variations, therefore, which are consistent in separating groups of species should be significant. Serological techniques were used because the biochemical systems involved seem to be relatively slow to change in response to environmental influences and because the data obtained may be used in a highly objective manner to measure resemblance among species.

Individual differences in the patterns of leg-musculature were found to be slight and involved mainly the sizes and shapes of muscles. For this reason variations involving origin, insertion, or relative position of a muscle, were judged significant. In leg-musculature the Richmondeninae, the Emberizinae, and the Thraupidae resemble one another closely. Several differences in muscle pattern were found, however, which distinguish these groups from the Carduelinae. The leg-musculature of the carduelines closely resembles that of the Ploceidae.

Serological techniques involved the extraction of saline-soluble proteins from the tissues of the species to be studied. These extracts were carefully processed and were used as antigens. Formolization of the antigens was necessary as a means of preventing denaturation of the proteins by enzymatic activity. Antisera were produced in rabbits. The method of testing involved turbidimetric analysis of the precipitin reaction. Utilizing the values for the precipitin tests a model was constructed which showed the relationships of the eleven species used in these tests. From a study of the model and the data used in its construction, it was determined that the Richmondeninae, Emberizinae, and Thraupidae constitute an assemblage distinct from the other species studied. The Carduelinae are excluded from the assemblage and serologically are most closely related to the Estrildinae. The estrildines, serologically, do not closely resemble Passer, Subfamily Passerinae, although recent classifications place these two subfamilies in the Family Ploceidae.

Upon consideration of all evidence now available--from external morphology, ethology, myology, osteology, and serology--several hypotheses regarding the relationships of the groups studied are set forth. The richmondenines, emberizines, and tanagers are closely related subfamilies and are here included in the Family Fringillidae. The Estrildinae and Carduelinae are closely related subfamilies, but neither group is closely related to the Passerinae. The estrildines and carduelines, therefore, are placed in a separate family, the Carduelidae. In some ways, Spiza is an aberrant member of the Subfamily Richmondeninae but should be retained in that subfamily. It is suggested that Spiza is a primitive richmondenine closely related to the ancestral fringillid stock.

LITERATURE CITED

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