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This study investigates the phylogenetic relationships within Paperclipidae using cladistic analysis, addressing issues of synapomorphy, autapomorphy, parsimony, reversal, convergence, consensus, and polytomies. The study also examines the ontogenetic variability and sexual dimorphism within the species, particularly regarding the diagnostic value of plastic traits.
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Paperclipidae Original Assumption (unstated): 1 individual = 1 species 7individuals Outgroup taxon not in set; described as headless straight pin or eyeless needle
THE ISSUES: SYNAPOMORPHY, AUTAPOMORPHY • Characters (0=absent, 1=present): • Wire bent • Wire doubles back on itself • Wire crosses over itself How do we construct a simple cladogram? Outgroup
Outgroup 3 2 1
THE ISSUES: PARSIMONY, REVERSAL • Characters (0=absent, 1=present): • Wire bent • Wire doubles back on itself • Wire crosses over itself • Head What hypothesis yields the shortest tree? Outgroup
Outgroup 4 3 2 1 Tree length = 4 steps Most parsimonious tree (MPT)
Outgroup 3 2 1 -4 4 Tree length = 5 steps
THE ISSUES: CONVERGENCE, CONSENSUS & POLYTOMIES • Characters (0=absent, 1=present): • Wire bent • Wire doubles back on itself • Wire crosses over itself • Head • Plastic Did plastic evolve more than once? Outgroup
Outgroup 5 5 3 4 2 1 Hypothesis 1 – Plastic evolved convergently in two lineages Tree length = 6 steps
Outgroup 4 4 -2 3 -1 5 2 Hypothesis 2a – Plastic evolved only once; head evolved convergently in two lineages 1 Tree length = 8 steps
Outgroup 2 3 1 -4 5 2 4 1 Hypothesis 2b – Plastic evolved only once; wire bending/doubling evolved convergently in two lineages Tree length = 8 steps
Outgroup 5 5 3 4 2 1 Plastic more likely evolved twice. This is not the only possible MPT. Tree length = 6 steps (MPT)
Outgroup 3 5 5 4 2 1 Tree length = 6 steps (MPT)
Outgroup 3 5 5 4 2 1 Tree length = 6 steps (MPT)
Outgroup Strict consensus of three MPTs showing polytomy.
Paperclipidae Original (unstated) Assumption: 1 individual = 1 species ARE YOU SURE? THE ISSUE: WHAT IS THIS INDIVIDUAL?
Size as ontogenetically variable / sexually dimorphic Species A adult, Species B, Species A juvenile OR Species A male, Species B, Species A female
Plastic as ontogenetically variable / sexually dimorphic Species A, Species B adult, Species B juvenile OR Species A, Species B male, Species B female OR Species A adult male, Species A juvenile, Species A adult female
Paperclipidae IF PLASTIC IS NOT DIAGNOSTIC AT SPECIES LEVEL, ARE THESE ALSO THE SAME SPECIES?