ACANTHOSOMATIDAE Signoret, 1863

Grazia, Jocelia, Schuh, Randall T. & Wheeler, Ward C., 2008, Phylogenetic relationships of family groups in Pentatomoidea based on morphology and DNA sequences (Insecta: Heteroptera), Cladistics 24, pp. 932-976 : 969-970

ACANTHOSOMATIDAE Signoret

Historical: This predominantly Southern Hemisphere taxon includes three subfamilies: Acanthosomatinae ,

Blaudinae with two tribes Blaudini and Lanopini, and Ditomotarsinae, also with two tribes, Ditomotarsini and Laccophorellini ( Kumar, 1974). Froeschner (1999) emendedthe spelling of Blaudusinae Kumar to Blaudinae

and Blaudini because the higher-taxon name was based on Blaudus Stål ; we follow Froeschner̕s usage. In the cladistic analysis of Gapud (1991) the Acanthosomatidae is related to the Dinidoridae plus Tessaratomidae and Scutelleridae , coming out in a relatively basal position on the cladogram ( Fig. 1f ). Fischer (1994a,b), in a phylogenetic analysisof the family, stressed the monophyly of the Acanthosomatidae based on three non-homoplastic characters and one homoplastic character: (i) presence of Pendergrast̕s organ (abdominal disc organ), (ii) segment VIII in males visible (not concealed by segment VII), (iii) females with a special organ for symbiont transmission, and (iv) openings of anterior abdominal scent glands shifted laterad, a feature shared with the Scutelleridae . Fischer (2006) described the biological context and evolution of Pendergrast̕s organ in the Acanthosomatidae , presenting a surveyof these organsin more than 100 acanthosamatid species.

Analytical result: Our morphological and total evidence analyses ( Figs 42–44 and 51–55 , respectively) always resolve the Acanthosomatidae as monophyletic, a theory concordant with most prior work. Our taxon sample for DNA sequences is biased toward the Australian fauna and the subfamilies Acanthosomatinae and Blaudinae, although we did sequence Elasmostethus Fieber from the Northern Hemisphere, a member of the Acanthosomatinae . The position of the group within the Pentatomoidea is variable, depending on the data set being analysed. The morphological analyses treat the group as relatively basal ( Figs 42–44 ), whereas the molecular data always treat the group as closely associated with the Pentatomidae ( Figs 45 and 46 ), although sometimes with a small number of other taxa involved ( Fig. 45 ). The 52-taxon total evidence analyses ( Figs 51 and 52 ) place the Acanthosomatidae + Lestoniidae as the sister group of the Pentatomidae , in the case of 1: 1 cost ratio also including Thaumastella . The result of the 92-taxon analysis under a 1: 1 cost ratio ( Fig. 53 ) is similar to molecular and 52-taxon analyses, the 1: 2 cost ratio moves the Acanthosomatidae to a more basal position in the cladogram ( Fig. 54 ), and the 2: 2 costratioincludesthe Dinidoridae + Tessaratomidae as part of the Acanthosomatidae + Pentatomidae complex. Morphological characters supporting the monophyly of the Acanthosomatidae in both the morphological and 92-taxon total evidence analyses are the membranous abdominal tergite VIII in males (411) and the triangulin absent with a smooth intergonocoxal membrane between gonapophyses 8 (531). The 92-taxon total evidence analyses offer additional support from the obsolete claval commissure (172) and the claws with bristles (311).

Figures

Fig. 1. Diagrams showing hypotheses of Pentatomoidea classifications (Bonatto, 1988): (a) Singh-Pruthi, 1925; diagram and discussion; (b) Leston, 1958; Fig. 5; (c) China and Miller, 1959; Fig. 1; (d) Cobben, 1968; figs 269–270; (e) Cobben, 1978; several figures and text; (f) proposed phylogeny of Pentatomoidea (Gapud, 1991). [Captions removed; all taxon names rendered in current spellings; part (f) not from Bonatto (1988).]

Fig. 42. Strict consensus of 96 most parsimonious trees for full-taxon morphological data set, with unsupported nodes supressed. Length = 207; consistency index = 42; retention index = 86. (d) Non-homoplasious; (s) homoplasious.

Fig. 43. Strict consensus of three trees derived from successive weighting of the results shown in Fig. 42. (d) Non-homoplasious; (s) homoplasious.

Fig. 44. Strict consensus of 12 trees derived from implied weighting analysis of morphological data using PIWE. (d) Non-homoplasious; (s) homoplasious.

Figs 49–52. 49. Single tree derived from analysis of ~470 bp of 28S rRNA using 1: 1 indel ⁄ transition–transversion cost ratio. 50. Single tree derived from analysis of ~1100 bp of COI mtDNA using 1: 1 indel ⁄transition–transversion cost ratio. 51. Total evidence analysis with POY of 52- taxon data set using 1: 1 indel ⁄ transition–transversion cost ratio. 52. Total evidence analysis with POY of 52-taxon data set using 2: 2 indel ⁄ transition–transversion cost ratio.

Fig. 53. One of six trees from total evidence analysis with POY of 92-taxon data set using 1: 1 indel ⁄ transition–transversion cost ratio. (d) Non-homoplasious; (s) homoplasious.

Fig. 54. One of four trees from total evidence analysis with POY of 92-taxon data set using 1: 2 indel ⁄ transition–transversion cost ratio. (d) Non-homoplasious; (s) homoplasious.

Fig. 55. One of three trees from total evidence analysis with POY of 92-taxon data set using 2: 2 indel ⁄transition–transversion cost ratio, which had the lowest MRI value. Bremer support values are shown.

Figs 45–48. 45. One of two trees derived from analysis of combined molecular data with 1: 1 indel ⁄transition–transversion cost ratio. 46. Single tree derived from analysis of combined molecular data with 2: 2 indel ⁄ transition–transversion cost ratio. 47. Single tree derived from analysis of ~500 bp of 16S rRNA data using 1: 1 indel ⁄ transition–transversion cost ratio. 48. Single tree derived from analysis of ~1800 bp of 18S rRNA using 1: 1 indel ⁄ transition–transversion cost ratio.