A Descriptive and Phylogenetic Analysis of Plumulaceous Feather Characters in Charadriiformes

3 INTRODUCTION . 3 REVIEW OF CHARADRIIFORM SYSTEMATICS . 6 PART 1--A DESCRIFFIVE SURVEY OF DOWNY FEATHER CHARACTERS IN CHARADRIIFORMES F•ATHeR STRUCTUP. E . 12 METHODS . 14 FEATHER PREPARATION . 15 LIGHT MICROSCOPY . 15 SCANNING ELECTRON MICROSCOPY . 16 DeSCRIPTIVe SURVEY . 17 INGROUPS . 17 CI4AV, ADVaIFORMes . 17 Jacanidae . 17 Rostratulidae . 18 Dromadidae . 19 Haematopodidae . 19 Ibidorhynchidae . 26 Recurvirostridae . 27 Burhinidae . 30 Glareolidae . 31 Charadriidae . 37 Scolopacidae . 42 Thinocoridae . 53 Pedionomidae . 59 Chionididae . 61 Stercorariidae . 62 Laridae . 62 2 ORNITHOLOGICAL MONOGRAPHS NO. 51 Rynchopidae . 73 Alcidae . ß . 75 OUTGROUPS . 76 GAVnFO•. MES . 76 Gaviidae . 76 GRInFORMES . 77 Gruidae . 80 Rallidae . 80 Otididae . 85 COLUMBIFORMES . 85 Pteroclidae . 86 RESULTS . 87 DOWN PIGMENTATION . 87 VmLI . 90 Charadriiform villi . 93 SEM examination of villi . 93 LM examination of villi . 102 BASE OF BARBULE . 102 Discussion . 105 PART 2--A PHYLOGENETIC ANALYSIS OF DOWNY FEATHER CHARACTERS IN CHARADRIIFORMES . 107 METHODS . 108 DERIVATION OF TREES . 108 [•EATHER CHARACTERS . 110 RESULTS . 119 OSTEOLOGICAL RESULTS . 122 DOWNY FEATHER RESULTS . 124 TOTAL-EVmENCE RESULTS . 127 CHARACTER ANALYSIS . 127 DISCUSSION . 129 CONVERGENCE . 130 CONCLUSIONS . 131 ACKNOWLEDGMENTS . 132 LITERATURE CITED . 133 APPENDICES . 136 1. FEATHER TERMINOLOGY . 136 2. SPECIMENS EXAMINED . 139 3. FEATHER CHARACTER MATRIX FOR CHARADRIIFORMES AND OUTGROUPS . 156 4. OSTEOLOGICAL CHARACTER MATRIX FOR OUTGROUP TAXA . 162 PLUMULACEOUS FEATHER CHARACTERS IN CHARADRIIFORMES 3 AaSTI•ACT. --The variation in microscopic characters of plumulaceous feathers is well known to be useful as an aid in species identifications. However, until now, the phylogenetic significance of these characters has not been thoroughly investigated. In the first part of this study, electron and light microscopy were used to examine the range of variation in downy feather characters of more than 145 species of shorebirds (Charadriiformes) and outgroup taxa. The major results of Part 1 demonstrate that similarities and differences exist in the microscopic features within this order, that different downy types (true down vs. contour feather down) of the same individual may have different microscopic structures, that some shorebirds have villi (previously unknown on the barbule bases of this group), and 38 microscopic feather characters are deemed useful for phylogenetic study. In Part 2, parsimony analysis was used to assess the phylogenetic value of these characters by comparing feather results to hypotheses based on osteological data and traditional classification. Three different taxa lists are analyzed using the computer software PAUP, Star (*) version. Although initial analyses of 111 taxa and 38 feather characters found more than 10,000 equally parsimonious trees, the analyses provided evidence that feather characters were tracking some natural groupings in this order. Additional analyses on two smaller sets of taxa used feather characters alone (38 characters), osteological characters alone (68 characters), and a combination of both character types to search for shortest rees. The final reduced-taxa analysis shows that feather character tree statistics and character indices are comparable to those of skeletal characters. Incongruence in tree topologies is noted in the placement of plovers with sandpipers according to feather characters. Indices of total-evidence trees for 154 shortest trees are higher than either of the data sets alone. Convergence in microscopic feather characters of loons and auks has been documented here for the first time and a functional hypothesis for nodal morphology is proposed. In this study of Charadriiformes, microscopic feather characters prove to be comparable to osteological characters in tracking phylogeny. However, better results are achieved when the data sets are combined. These results support the utility of microscopic feather characters in phylogenetic studies and in microscopic identification of arian species from fragmentary evidence.