Conciliterga

{{Automatic taxobox

| fossil_range = {{fossil range|Cambrian Stage 3|Wuliuan}}

| image = USNM PAL 83952 Helmetia expansa Image 03.jpg

| image_caption = Holotype of Helmetia expansa

| image2 = Kuamaia lata.png

| image2_caption = Life restoration of Kuamaia lata

| display_parents = 2

| taxon = Conciliterga

| authority = Hou & Bergström, 1997{{cite journal |last1=Xianguang |first1=Hou |last2=Bergström |first2=Jan |title=Arthropods of the Lower Cambrian Chengjiang fauna, southwest China |journal=Fossils and Strata |date=22 December 1997 |volume=45 |pages=1–117 |doi=10.18261/8200376931-1997-01}}

| type_species = †Helmetia expansa

| type_species_authority = Walcott, 1918

| subdivision_ranks = Genera

| subdivision = *†Arthroaspis

†Kwanyinaspis?
†Tegopeltidae
†Tegopelte
†Saperion
†Skioldia
†Helmetiidae
†Helmetia
†Rhombicalvaria
†Haifengella
†Kuamaia

}}

Conciliterga is an extinct order of artiopod arthropods, exclusively known from the Middle Cambrian. They are placed within the clade Trilobitomorpha, which contains the trilobites and their closest relatives.{{Cite journal |last=Du |first=Kun‐sheng |last2=Ortega‐Hernández |first2=Javier |last3=Yang |first3=Jie |last4=Zhang |first4=Xi‐guang |date=June 2019 |title=A soft‐bodied euarthropod from the early Cambrian Xiaoshiba Lagerstätte of China supports a new clade of basal artiopodans with dorsal ecdysial sutures |url=https://onlinelibrary.wiley.com/doi/10.1111/cla.12344 |journal=Cladistics |language=en |volume=35 |issue=3 |pages=269–281 |doi=10.1111/cla.12344 |issn=0748-3007}}

Conciliterga is united by their partially or wholly fused tergites, which gives rise to their name (Conciliterga is composed of the Latin words concilio ("to unite") and tergum ("back")). Most members of this clade are elliptical in body shape, with 6-9 thoracic tergites, a head shield and a large tail shield in the members with incomplete tergite fusion. These members, which formerly comprised the order Helmetiida (which currently only contains Helmetia, Rhombicalvaria and Kuamaia), also have various other characteristics like a lack of axial region, rostral and pararostral plates on the head, and compound eyes near the rostral plate. In addition, they have essentially uniform biramous limbs running down the body with coarse endopods, alongside a pair of antennae. A second clade is also observed, containing Tegopelte, Saperion and Skioldia. This clade is characterised by wholly fused tergites (although Skioldia still shows traces of their outlines, and so is likely more basal), alongside more ventral eyes. Haifengella, while appearing very helmetiid-like, has been recovered as the basalmost concilitergan,{{cite journal |last1=Jiao |first1=De-Guang |last2=Du |first2=Kun-Sheng |last3=Zhang |first3=Xi-Guang |last4=Yang |first4=Jie |last5=Eggink |first5=Daniel |title=A new small soft-bodied non-trilobite artiopod from the Cambrian Stage 4 Guanshan Biota |journal=Geological Magazine |date=May 2022 |volume=159 |issue=5 |pages=730–734 |doi=10.1017/S0016756821001254|doi-access=free }} suggesting the Tegopelte-like clade is especially derived. Kwanyinaspiss inclusion within Conciliterga is unclear, as while many studies place it near Aglaspidida, a 2010 study found it as a stem-concilitergan instead.{{cite journal |last1=Paterson |first1=John R. |last2=Edgecombe |first2=Gregory D. |last3=GarcíA‐Bellido |first3=Diego C. |last4=Jago |first4=James B. |last5=Gehling |first5=James G. |title=Nektaspid arthropods from the Lower Cambrian Emu Bay Shale Lagerstätte, South Australia, with a reassessment of lamellipedian relationships |journal=Palaeontology |date=March 2010 |volume=53 |issue=2 |pages=377–402 |doi=10.1111/j.1475-4983.2010.00932.x}} However a 2022 study instead recovered it as the closest relative to trilobites. Members of Conciliterga are known from only a few locations around the world, mainly the Maotianshan Shales and Burgess Shale. Another paper published by Losso et al. 2025, which re-analyzed Helmetia, erected two new families within the conciliterga, the Helmetiidae and the Tegopeltidae'.{{Cite journal |last=Losso |first=Sarah R. |last2=Caron |first2=Jean-Bernard |last3=Ortega-Hernández |first3=Javier |date=2025-04-04 |title=Helmetia expansa Walcott, 1918 revisited – new insights into the internal anatomy, moulting and phylogeny of Conciliterga |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2025.2468195 |journal=Journal of Systematic Palaeontology |volume=23 |issue=1 |pages=2468195 |doi=10.1080/14772019.2025.2468195 |issn=1477-2019 |doi-access=free|url-access=subscription }} Losso et al. 2025 also resolved the taxonomic relationships of Arthroaspis, an artiopod from the Sirius Passet locality in northern Greenland, placing it as an early diverging taxon within the conciliterga.