On dorsal prothoracic appendages in treehoppers (Hemiptera: Membracidae) and the nature of morphological evidence

István Mikó, Frank Friedrich, Matthew Jon Yoder, Heather M. Hines, Lewis L. Deitz, Matthew A. Bertone, Katja C. Seltmann, Matthew S. Wallace, Andrew R. Deans

Research output: Contribution to journalArticle

Abstract

A spectacular hypothesis was published recently, which suggested that the "helmet" (a dorsal thoracic sclerite that obscures most of the body) of treehoppers (Insecta: Hemiptera: Membracidae) is connected to the 1st thoracic segment (T1; prothorax) via a jointed articulation and therefore was a true appendage. Furthermore, the "helmet" was interpreted to share multiple characteristics with wings, which in extant pterygote insects are present only on the 2nd (T2) and 3rd (T3) thoracic segments. In this context, the "helmet" could be considered an evolutionary novelty. Although multiple lines of morphological evidence putatively supported the "helmet"-wing homology, the relationship of the "helmet" to other thoracic sclerites and muscles remained unclear. Our observations of exemplar thoraces of 10 hemipteran families reveal multiple misinterpretations relevant to the "helmet"-wing homology hypothesis as originally conceived: 1) the "helmet" actually represents T1 (excluding the fore legs); 2) the "T1 tergum" is actually the anterior dorsal area of T2; 3) the putative articulation between the "helmet" and T1 is actually the articulation between T1 and T2. We conclude that there is no dorsal, articulated appendage on the membracid T1. Although the posterior, flattened, cuticular evagination (PFE) of the membracid T1 does share structural and genetic attributes with wings, the PFE is actually widely distributed across Hemiptera. Hence, the presence of this structure in Membracidae is not an evolutionary novelty for this clade. We discuss this new interpretation of the membracid T1 and the challenges of interpreting and representing morphological data more broadly. We acknowledge that the lack of data standards for morphology is a contributing factor to misinterpreted results and offer an example for how one can reduce ambiguity in morphology by referencing anatomical concepts in published ontologies.

Original languageEnglish (US)
Article numbere30137
JournalPloS one
Volume7
Issue number1
DOIs
StatePublished - Jan 17 2012
Externally publishedYes

Fingerprint

Membracidae
Head Protective Devices
Hemiptera
chest
appendages
Thorax
thorax
Insecta
Ontology
Insects
Muscle
legs
muscles
insects
Leg
Muscles

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

On dorsal prothoracic appendages in treehoppers (Hemiptera : Membracidae) and the nature of morphological evidence. / Mikó, István; Friedrich, Frank; Yoder, Matthew Jon; Hines, Heather M.; Deitz, Lewis L.; Bertone, Matthew A.; Seltmann, Katja C.; Wallace, Matthew S.; Deans, Andrew R.

In: PloS one, Vol. 7, No. 1, e30137, 17.01.2012.

Research output: Contribution to journalArticle

Mikó, I, Friedrich, F, Yoder, MJ, Hines, HM, Deitz, LL, Bertone, MA, Seltmann, KC, Wallace, MS & Deans, AR 2012, 'On dorsal prothoracic appendages in treehoppers (Hemiptera: Membracidae) and the nature of morphological evidence', PloS one, vol. 7, no. 1, e30137. https://doi.org/10.1371/journal.pone.0030137
Mikó, István ; Friedrich, Frank ; Yoder, Matthew Jon ; Hines, Heather M. ; Deitz, Lewis L. ; Bertone, Matthew A. ; Seltmann, Katja C. ; Wallace, Matthew S. ; Deans, Andrew R. / On dorsal prothoracic appendages in treehoppers (Hemiptera : Membracidae) and the nature of morphological evidence. In: PloS one. 2012 ; Vol. 7, No. 1.
@article{6bfa752bb82e4e7db0fa9e003c75e982,
title = "On dorsal prothoracic appendages in treehoppers (Hemiptera: Membracidae) and the nature of morphological evidence",
abstract = "A spectacular hypothesis was published recently, which suggested that the {"}helmet{"} (a dorsal thoracic sclerite that obscures most of the body) of treehoppers (Insecta: Hemiptera: Membracidae) is connected to the 1st thoracic segment (T1; prothorax) via a jointed articulation and therefore was a true appendage. Furthermore, the {"}helmet{"} was interpreted to share multiple characteristics with wings, which in extant pterygote insects are present only on the 2nd (T2) and 3rd (T3) thoracic segments. In this context, the {"}helmet{"} could be considered an evolutionary novelty. Although multiple lines of morphological evidence putatively supported the {"}helmet{"}-wing homology, the relationship of the {"}helmet{"} to other thoracic sclerites and muscles remained unclear. Our observations of exemplar thoraces of 10 hemipteran families reveal multiple misinterpretations relevant to the {"}helmet{"}-wing homology hypothesis as originally conceived: 1) the {"}helmet{"} actually represents T1 (excluding the fore legs); 2) the {"}T1 tergum{"} is actually the anterior dorsal area of T2; 3) the putative articulation between the {"}helmet{"} and T1 is actually the articulation between T1 and T2. We conclude that there is no dorsal, articulated appendage on the membracid T1. Although the posterior, flattened, cuticular evagination (PFE) of the membracid T1 does share structural and genetic attributes with wings, the PFE is actually widely distributed across Hemiptera. Hence, the presence of this structure in Membracidae is not an evolutionary novelty for this clade. We discuss this new interpretation of the membracid T1 and the challenges of interpreting and representing morphological data more broadly. We acknowledge that the lack of data standards for morphology is a contributing factor to misinterpreted results and offer an example for how one can reduce ambiguity in morphology by referencing anatomical concepts in published ontologies.",
author = "Istv{\'a}n Mik{\'o} and Frank Friedrich and Yoder, {Matthew Jon} and Hines, {Heather M.} and Deitz, {Lewis L.} and Bertone, {Matthew A.} and Seltmann, {Katja C.} and Wallace, {Matthew S.} and Deans, {Andrew R.}",
year = "2012",
month = "1",
day = "17",
doi = "10.1371/journal.pone.0030137",
language = "English (US)",
volume = "7",
journal = "PLoS One",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "1",

}

TY - JOUR

T1 - On dorsal prothoracic appendages in treehoppers (Hemiptera

T2 - Membracidae) and the nature of morphological evidence

AU - Mikó, István

AU - Friedrich, Frank

AU - Yoder, Matthew Jon

AU - Hines, Heather M.

AU - Deitz, Lewis L.

AU - Bertone, Matthew A.

AU - Seltmann, Katja C.

AU - Wallace, Matthew S.

AU - Deans, Andrew R.

PY - 2012/1/17

Y1 - 2012/1/17

N2 - A spectacular hypothesis was published recently, which suggested that the "helmet" (a dorsal thoracic sclerite that obscures most of the body) of treehoppers (Insecta: Hemiptera: Membracidae) is connected to the 1st thoracic segment (T1; prothorax) via a jointed articulation and therefore was a true appendage. Furthermore, the "helmet" was interpreted to share multiple characteristics with wings, which in extant pterygote insects are present only on the 2nd (T2) and 3rd (T3) thoracic segments. In this context, the "helmet" could be considered an evolutionary novelty. Although multiple lines of morphological evidence putatively supported the "helmet"-wing homology, the relationship of the "helmet" to other thoracic sclerites and muscles remained unclear. Our observations of exemplar thoraces of 10 hemipteran families reveal multiple misinterpretations relevant to the "helmet"-wing homology hypothesis as originally conceived: 1) the "helmet" actually represents T1 (excluding the fore legs); 2) the "T1 tergum" is actually the anterior dorsal area of T2; 3) the putative articulation between the "helmet" and T1 is actually the articulation between T1 and T2. We conclude that there is no dorsal, articulated appendage on the membracid T1. Although the posterior, flattened, cuticular evagination (PFE) of the membracid T1 does share structural and genetic attributes with wings, the PFE is actually widely distributed across Hemiptera. Hence, the presence of this structure in Membracidae is not an evolutionary novelty for this clade. We discuss this new interpretation of the membracid T1 and the challenges of interpreting and representing morphological data more broadly. We acknowledge that the lack of data standards for morphology is a contributing factor to misinterpreted results and offer an example for how one can reduce ambiguity in morphology by referencing anatomical concepts in published ontologies.

AB - A spectacular hypothesis was published recently, which suggested that the "helmet" (a dorsal thoracic sclerite that obscures most of the body) of treehoppers (Insecta: Hemiptera: Membracidae) is connected to the 1st thoracic segment (T1; prothorax) via a jointed articulation and therefore was a true appendage. Furthermore, the "helmet" was interpreted to share multiple characteristics with wings, which in extant pterygote insects are present only on the 2nd (T2) and 3rd (T3) thoracic segments. In this context, the "helmet" could be considered an evolutionary novelty. Although multiple lines of morphological evidence putatively supported the "helmet"-wing homology, the relationship of the "helmet" to other thoracic sclerites and muscles remained unclear. Our observations of exemplar thoraces of 10 hemipteran families reveal multiple misinterpretations relevant to the "helmet"-wing homology hypothesis as originally conceived: 1) the "helmet" actually represents T1 (excluding the fore legs); 2) the "T1 tergum" is actually the anterior dorsal area of T2; 3) the putative articulation between the "helmet" and T1 is actually the articulation between T1 and T2. We conclude that there is no dorsal, articulated appendage on the membracid T1. Although the posterior, flattened, cuticular evagination (PFE) of the membracid T1 does share structural and genetic attributes with wings, the PFE is actually widely distributed across Hemiptera. Hence, the presence of this structure in Membracidae is not an evolutionary novelty for this clade. We discuss this new interpretation of the membracid T1 and the challenges of interpreting and representing morphological data more broadly. We acknowledge that the lack of data standards for morphology is a contributing factor to misinterpreted results and offer an example for how one can reduce ambiguity in morphology by referencing anatomical concepts in published ontologies.

UR - http://www.scopus.com/inward/record.url?scp=84855849502&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84855849502&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0030137

DO - 10.1371/journal.pone.0030137

M3 - Article

C2 - 22272287

AN - SCOPUS:84855849502

VL - 7

JO - PLoS One

JF - PLoS One

SN - 1932-6203

IS - 1

M1 - e30137

ER -