# Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses (ICTV) from the Archaeal Viruses Subcommittee, 2025

Mart Krupovic, Diana Paola Baquero, Eduardo A Bignon, Ariane Bize, Guillaume Borrel, Mingwei Cai, Lanming Chen, Marion Coves, Changhai Duan, Simonetta Gribaldo, et al.

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## To cite this version:

Mart Krupovic, Diana Paola Baquero, Eduardo A Bignon, Ariane Bize, Guillaume Borrel, et al. Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses (ICTV) from the Archaeal Viruses Subcommittee, 2025. Journal of General Virology, 2025, 106 (7), pp.002117. 10.1099/jgv.0.002117. pasteur-05212168

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# Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses (ICTV) from the Archaeal Viruses Subcommittee, 2025

Mart Krupovic¹*, Diana P. Baquero¹, Eduardo A. Bignon¹, Ariane Bize², Guillaume Borrel³, Mingwei Cai⁴, Lanming Chen⁵,
Marion Coves², Changhai Duan⁶,⁷, Simonetta Gribaldo³, Eugene V. Koonin⁷, Meng Li⁴, Lirui Liu⁴, Yang Liu⁴, Ying Liu¹,
Sofia Medvedeva¹, Yimin Ni⁵, Apoorva Prabhu⁸, Christian Rinke⁹, Yongjie Wang⁵, Tianqi Xu⁵, Shuling Yan¹⁰, Qinglu Zeng¹¹,
Rui Zhang⁴ and ICTV Taxonomy Summary Consortium

## Abstract

An erratum of this article has been published full details can be found at 10.1099/jgv.0.002145

The International Committee on Taxonomy of Viruses (ICTV) holds a ratification vote annually following the review of newly proposed taxa by ICTV Study Groups and members of the virology community. This article reports changes to the taxonomy of viruses infecting archaea that were approved and ratified by the ICTV in March 2025. Six new families of head-tailed viruses expanded the order *Caudoviricetes* (realm *Duplodnaviria*); one new family of filamentous viruses was added to the order *Ligamenvirales* (realm *Adnaviria*); one new family of viruses with pleomorphic virions was included within a new phylum, new order and new class in the kingdom *Trapavirae* (realm *Monodnaviria*); finally, three new families were created for spindle-shaped viruses that remain unassigned to higher level taxa. The 25 new species represent viruses infecting a broad range of archaea, including members of the classes Archaeoglobi, Bathyarchaeia, Methanobacteria, Methanomicrobia, Nitrososphaeria and Poseidoniia. Most of these viruses have been discovered by metagenomics in samples derived from diverse environments, including ambient and extreme marine ecosystems, the gastrointestinal tract of humans and animals, anaerobic digesters and terrestrial hot springs. Following this taxonomic update, archaeal viruses are officially classified into a total of 163 virus species in 94 genera within 62 families.

## INTRODUCTION

Archaeal viruses comprise the least explored part of the global virosphere [1]. Of the 14,690 virus species established until 2025, only 138, i.e. <1%, represented viruses infecting archaea [2]. Nevertheless, these viruses display remarkable diversity of virion structure and gene content, which distinguish them from viruses of bacteria and eukaryotes [3–6]. Historically, archaeal viruses have been primarily isolated from geothermal and hypersaline habitats, with only a handful of viruses from ambient ecosystems. Thus, the officially classified archaeal virosphere has been biased towards viruses of thermophilic and halophilic archaea. However, advances in metagenomics and the decision of the International Committee on Taxonomy of Viruses (ICTV) to classify viruses based on their genome sequence alone, without the need for isolation and demonstration of infectivity [7, 8], have enabled the classification of viruses from more diverse environments and infecting hosts that cannot be (easily) cultivated under laboratory conditions.

The ICTV Archaeal Viruses Subcommittee oversees the advancement of taxonomy of viruses infecting archaea and currently includes 11 Study Groups [9]. During 2024, seven taxonomic proposals for the creation of 25 new species within 17 new genera and 11 new families were submitted to the ICTV Archaeal Viruses Subcommittee. All submitted proposals were accepted by the ICTV Executive Committee and subsequently ratified by the entire ICTV membership in March 2025.

The 25 new species represent viruses infecting a broad range of archaea from diverse environments, including ambient and extreme marine ecosystems, the gastrointestinal tract of humans and animals, anaerobic digesters and terrestrial hot
springs. Head-tailed viruses, predicted to infect Marine Group II Archaea (order Poseidoniales), have been classified into three new families, expanding the recently created order *Magrovirales* [10] and adding a new order, *Adrikavirales*, to the class *Caudoviricetes* [11]. Ten spindle-shaped viruses distantly related to members of the family *Thaspiviridae* [12] and predicted to infect ammonia-oxidizing archaea (order Nitrososphaerales) were classified into the new family *Nipumfusiviridae* [13]. Non-lytic viruses with enveloped pleomorphic virions associated with the archaea of the class Archaeoglobi, a group of hyperthermophilic archaea inhabiting deep-sea hydrothermal vents, were classified into the family *Thalassapleoviridae*, within a new order *Ageovirales*, new class *Caminiviricetes* and new phylum *Calorviricota* [14]. Diverse viruses associated with Bathyarchaeia, a group of archaea common and abundant in sedimentary ecosystems, were classified into four new families [15]. Head-tailed bathyarchaeal viruses were classified into the families *Fuxiviridae* and *Kunpengviridae*; filamentous viruses into *Chiyouviridae*, a new family within the order *Ligamenvirales* of the realm *Adnaviria* [16]; and spindle-shaped viruses into the family *Huangdiviridae*. Head-tailed viruses infecting *Methanobrevibacter* species, the dominant methanogenic archaea in the gut of humans and other animals, were classified into the family *Usuviridae* [17], further expanding the order *Methanobavirales* [18, 19] within the class *Caudoviricetes*. Finally, a spindle-shaped virus associated with methanogenic archaea of the genus *Methanosarcina* detected in anaerobic digestion batch microcosms was classified into the family *Eurekaviridae*. All species were named using a binomial format (genus name+species epithet), as mandated by the ICTV [20]. Except for two viruses, namely, the usuvirid Methanobrevibacter tailed virus 1 [17] and the thalassapleovirid Archaeoglobus veneficus pleomorphic virus 1 [14], which have been isolated, all other newly classified archaeal viruses were discovered by metagenomics, reflecting the general trend in current virus discovery efforts.

Following this taxonomic update, archaeal viruses are officially classified into a total of 163 virus species in 94 genera within 62 families. The individual summaries of the seven taxonomic proposals are described in more detail in the following section, and the full proposals can be accessed via the ICTV website (ictv.global). A file including all the Tables of taxonomic changes below is available as a supplementary file to this article.

# MAIN TEXT

## Contents

* 2024.001A.Apasviridae_newfam

* 2024.002A.Adrikavirales_neworder_2newfam

* 2024.003A.Nipumfusiviridae_newfam

* 2024.004A.Thalassapleoviridae_newphylum

* 2024.005A.Bathyarchaeia_4newfam

* 2024.006A.Usuviridae_newfam

* 2024.007A.Eurekaviridae_newfam

## 2024.001A.Apasviridae_newfam

**Title:** Create one new family in the order *Magrovirales* (class *Caudoviricetes*)

**Authors:** Prabhu A (apoorva.prabhu@uq.edu.au), Rinke C

## Summary

### Taxonomic rank(s) affected

Magrovirus group A (order *Magrovirales*; class *Caudoviricetes*)

### Description of current taxonomy

Recently, the order *Magrovirales* was created for viruses associated with Marine Group II Archaea (order Poseidoniales), belonging to the class *Caudoviricetes*. Within *Magrovirales*, the family *Aoguangviridae* includes the group 'Magrovirus B' [21].

### Proposed taxonomic change(s)

Here, we propose creating the family *Apasviridae* for the group 'Magrovirus A', with one new genus *Agnivirus*, which includes the species *Agnivirus brisanense*.

### Justification

Most genome sequences of magroviruses belonging to group A have not been deposited into public databases, i.e. GenBank. Hence, we propose the classification of viruses based on the demarcation criteria previously established for classification of archaeal-tailed viruses infecting halophilic and methanogenic archaea.

**Submitted:** 24/07/2023; **Revised:** 07/10/2024
<table><caption>**Table 1.** *Apasviridae*, three new taxa*</caption><thead><tr><td>Operation</td><td>Rank</td><td>New taxon name</td><td>Virus name</td><td>Exemplar</td></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Apasviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Agnivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Agnivirus brisbanense</td><td>magrovirus_A_01</td><td>OR863078</td></tr></tbody></table>

*Source/full text: https://ictv.global/proposals/2024.001A.Apasviridae_newfam.zip*

## 2024.002A.Adrikavirales_neworder_2newfam

**Title:** Create one new family in the order *Magrovirales* (class *Caudoviricetes*) and one new order *Adrikavirales* within the class *Caudoviricetes*

**Authors:** Prabhu A (apoorva.prabhu@uq.edu.au), Rinke C

### Summary

**Taxonomic rank(s) affected**

Magrovirus group E (unofficially assigned to the order *Magrovirales*; class *Caudoviricetes*) and a new order within the class *Caudoviricetes*.

**Description of current taxonomy**

Recently, the order *Magrovirales* was created for viruses associated with Marine Group II Archaea (order Poseidoniales), belonging to the class *Caudoviricetes*. Within *Magrovirales*, the family *Aoguangviridae* includes the group 'Magrovirus B' [21].

**Proposed taxonomic change(s)**

Here, we propose creating the family *Krittikaviridae*, representing the group 'Magrovirus E', with one new genus *Velanvirus*, which will include the species *Velanvirus brisbanense*. In addition, we identified a virus associated with Poseidoniales, which belongs to a novel order (*Adrikavirales*), family (*Satyavativiridae*), genus (*Vyasavirus*) and species (*Vyasavirus brisbanense*) within the class *Caudoviricetes*.

**Justification**

Most currently available genomes of magroviruses assigned to group E are not of high quality and do not have GenBank entries. Furthermore, Poseidoniales-associated viruses assigned to an order other than *Magrovirales* have not been described. Hence, we propose the classification of viruses based on the demarcation criteria previously established for classification of archaeal-tailed viruses infecting halophilic and methanogenic archaea.

**Submitted:** 18/03/2024; **Revised:** 07/10/2024

<table><caption>**Table 2.** Seven new taxa within the class *Caudoviricetes*</caption><thead><tr><td>Operation</td><td>Rank</td><td>New taxon name</td><td>Virus name</td><td>Exemplar</td></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Krittikaviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Velanvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Velanvirus brisbanense</td><td>magrovirus_E_01</td><td>PP497039</td></tr><tr><td>New taxon</td><td>Order</td><td>Adrikavirales</td><td></td><td></td></tr><tr><td>New taxon</td><td>Family</td><td>Satyavativiridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Vyasavirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Vyasavirus brisbanense</td><td>Poseidoniales virus P01</td><td>PP497040</td></tr></tbody></table>

*Source/full text: https://ictv.global/proposals/2024.002A.Adrikavirales_neworder_2newfam.zip*

## 2024.003A.Nipumfusiviridae_newfam

**Title:** Create one new family *Nipumfusiviridae* with four genera and ten species for archaeal viruses

**Authors:** Yimin Ni (Nemo.ni@outlook.com), Tianqi Xu, Shuling Yan, Lanming Chen, Yongjie Wang
## Summary

### Taxonomic rank(s) affected

We propose creating a new family, *Nipumfusiviridae*, for classification of spindle-shaped viruses infecting ammonia-oxidizing archaea. The family is not currently assigned to any higher level taxon.

### Description of current taxonomy

Three families of small spindle-shaped archaeal viruses are currently defined: *Fuselloviridae*, *Halspiviridae* and *Thaspiviridae*. In addition, several spindle-shaped viruses are still unclassified. No spindle-shaped viruses infecting a methanogen have been classified so far.

### Proposed taxonomic change(s)

We propose a new family for Nitrosopumilaceae virus NYM1 and its relatives, the *Nipumfusiviridae* ('Ni' and 'pum' for having sequence features similar to archaea from the family Nitrosopumilaceae and for being the deduced host; 'fusi' after the Latin word meaning spindles for the possible morphology). The four proposed genera are named *Yangshanfusivirus*, *Terrafusivirus*, *Marefusivirus* and *Baiafusivirus* after their original sampling sites, and species names are given based on the sampling locations.

### Justification

Members of the *Nipumfusiviridae* are distantly related to members of the family *Thaspiviridae*. To be classified within *Nipumfusiviridae*, new members should share at least 30% average amino acid identity with the genomes of other viruses classified within the family *Nipumfusiviridae* and share a minimum set of homologous proteins, including the major capsid protein and the ATPase.

**Submitted:** 20/05/2024

<table><caption>**Table 3.** *Nipumfusiviridae*, 15 new taxa*</caption><thead><tr><td>Operation</td><td>Rank</td><td>New taxon name</td><td>Virus name</td><td>Exemplar</td></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Nipumfusiviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Marefusivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Marefusivirus pacificense</td><td>Nitrosopumilaceae spindle-shaped virus NMP1</td><td>BK067782</td></tr><tr><td>New taxon</td><td>Species</td><td>Marefusivirus helgoense</td><td>Nitrosopumilaceae spindle-shaped virus NMH1</td><td>BK067784</td></tr><tr><td>New taxon</td><td>Species</td><td>Marefusivirus jervisense</td><td>Nitrosopumilaceae spindle-shaped virus NMJ1</td><td>BK067785</td></tr><tr><td>New taxon</td><td>Species</td><td>Marefusivirus columbiaense</td><td>Nitrosopumilaceae spindle-shaped virus NMC1</td><td>BK067789</td></tr><tr><td>New taxon</td><td>Species</td><td>Marefusivirus montereyense</td><td>Nitrosopumilaceae spindle-shaped virus NMM1</td><td>BK067790</td></tr><tr><td>New taxon</td><td>Genus</td><td>Terrafusivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Terrafusivirus michiganense</td><td>Nitrosopumilaceae spindle-shaped virus NTM1</td><td>BK067788</td></tr><tr><td>New taxon</td><td>Species</td><td>Terrafusivirus tennesseense</td><td>Nitrosopumilaceae spindle-shaped virus NTT1</td><td>BK067791</td></tr><tr><td>New taxon</td><td>Genus</td><td>Baiafusivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Baiafusivirus delawareense</td><td>Nitrosopumilaceae spindle-shaped virus NBD1</td><td>BK067787</td></tr><tr><td>New taxon</td><td>Species</td><td>Baiafusivirus chesapeakense</td><td>Nitrosopumilaceae spindle-shaped virus NBC1</td><td>BK067786</td></tr><tr><td>New taxon</td><td>Genus</td><td>Yangshanfusivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Yangshanfusivirus mimetica</td><td>Nitrosopumilaceae spindle-shaped virus NYM1</td><td>BK067792</td></tr></tbody></table>

## 2024.004A.Thalassapleoviridae_newphylum

**Title:** Create a phylum within kingdom *Trapavirae* (realm *Monodnaviria*) for classification of hyperthermophilic archaeal viruses with pleomorphic virions

**Authors:** Baquero DP, Bignon EA, Krupovic M (mart.krupovic@pasteur.fr)

## Summary

### Taxonomic rank(s) affected

<footnote>*Source/full text: https://ictv.global/proposals/2024.003A.Nipumfusiviridae_newfam.zip</footnote>
### *Monodnaviria, Trapavirae*

### Description of current taxonomy

The monodnavirian kingdom *Trapavirae* currently comprises a single family, *Pleolipoviridae*, which includes haloarchaeal viruses with enveloped pleomorphic virions and ssDNA or dsDNA genomes.

### Proposed taxonomic change(s)

Here, we propose to classify viruses infecting hyperthermophilic marine archaea, distantly related to pleolipovirids, into a new family, *Thalassapleoviridae*, and include it in a new phylum within the kingdom *Trapavirae*.

### Justification

Whole-genome phylogenomic analysis and maximum likelihood phylogenetic analysis based on the membrane fusion protein characteristic of members of the kingdom *Trapavirae* show that members of the proposed family *Thalassapleoviridae* form a monophyletic group separate from the haloarchaeal pleolipovirids and currently unclassified related viruses of methanogenic archaea.

**Submitted:** 21/06/2024

<table><caption>**Table 4.** *Thalassapleoviridae*, 12 new taxa*</caption><thead><tr><th>Operation</th><th>Rank</th><th>New taxon name</th><th>Virus name</th><th>Exemplar</th></tr></thead><tbody><tr><td>New taxon</td><td>Phylum</td><td>Calorviricota</td><td></td><td></td></tr><tr><td>New taxon</td><td>Class</td><td>Caminiviricetes</td><td></td><td></td></tr><tr><td>New taxon</td><td>Order</td><td>Ageovirales</td><td></td><td></td></tr><tr><td>New taxon</td><td>Family</td><td>Thalassapleoviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Avenivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Aprofivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Geogavirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Avenivirus atlanticense</td><td>Archaeoglobus veneficus pleomorphic virus 1</td><td>BK065155</td></tr><tr><td>New taxon</td><td>Species</td><td>Aprofivirus guaymasense</td><td>Archaeoglobus profundus pleomorphic virus 1</td><td>BK065154</td></tr><tr><td>New taxon</td><td>Species</td><td>Geogavirus atlanticense</td><td>Geoglobus acetivorans pleomorphic virus 1</td><td>BK065156</td></tr><tr><td>New taxon</td><td>Species</td><td>Geogavirus guaymasense</td><td>Geoglobus ahangari pleomorphic virus 1</td><td>BK065157</td></tr><tr><td>New taxon</td><td>Species</td><td>Geogavirus pacificense</td><td>Thalassapleovirus 2</td><td>BK065158</td></tr></tbody></table>

*Source/full text: https://ictv.global/proposals/2024.004A.Thalassapleoviridae_newphylum.zip*

## 2024.005A.Bathyarchaeia_4newfam

**Title:** Create four new families for Bathyarchaeia viruses

**Authors:** Duan CH, Liu Y, Liu LR, Cai MW, Zhang R, Zeng QL, Koonin V E, Krupovic M, Li M (limeng848@szu.edu.cn)

### Summary

Bathyarchaeia is an archaeal class widespread in marine and freshwater sediments. Here, we propose four new families for viruses identified by metagenomics and associated with hosts of the Bathyarchaeia class. The families *Fuxiviridae* and *Kunpengviridae* include head-tailed viruses of the class *Caudoviricetes* in the realm *Duplodnaviria*. The family *Chiyouviridae* includes filamentous viruses of the archaea-specific realm *Adnaviria*. The fourth putative family, *Huangdiviridae*, with only one representative genome, includes an archaea-specific spindle-shaped virus; the spindle-shaped viruses have not yet been classified at higher taxonomy ranks.

**Submitted:** 20/06/2024; **Revised:** 04/09/2024

<table><caption>**Table 5.** Bathyarchaeia, 12 new taxa*</caption><thead><tr><th>Operation</th><th>Rank</th><th>New taxon name</th><th>Virus name</th><th>Exemplar</th></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Fuxiviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Family</td><td>Kunpengviridae</td><td></td><td></td></tr></tbody></table>

Continued
<table><caption>**Table 5. Continued**</caption><thead><tr><th>Operation</th><th>Rank</th><th>New taxon name</th><th>Virus name</th><th>Exemplar</th></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Chiyouviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Family</td><td>Huangdiviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Taijivirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Dafengvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Wargodvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Xuanyuanvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Taijivirus yinyang</td><td>Bathyarchaeia bifangarchaeales fuxivirus 1</td><td>PP467601</td></tr><tr><td>New taxon</td><td>Species</td><td>Dafengvirus linsing</td><td>Bathyarchaeia jinwuousiales Kupengvirus 1</td><td>PP467599</td></tr><tr><td>New taxon</td><td>Species</td><td>Wargodvirus xiongnu</td><td>Bathyarchaeia bifangarchaeales chiyouvirus 1</td><td>PP467602</td></tr><tr><td>New taxon</td><td>Species</td><td>Xuanyuanvirus yandi</td><td>Bathyarchaeia baizomonadales Huangdivirus 1</td><td>QMYA01000001</td></tr></tbody></table>

## 2024.006A.Usuviridae_newfam

**Title:** Create new family, *Usuviridae*, with two genera in the order *Methanobavirales* (class *Caudoviricetes*)

**Authors:** Diana P. Baquero, Sofia Medvedeva, Guillaume Borrel, Simonetta Gribaldo, Mart Krupovic (mart.krupovic@pasteur.fr)

### Summary

**Taxonomic rank(s) affected**

*Duplodnaviria, Heunggongvirae, Uroviricota, Caudoviricetes, Methanobavirales*

**Description of current taxonomy**

The order *Methanobavirales* (class *Caudoviricetes*) currently includes five families of viruses infecting methanogenic archaea.

**Proposed taxonomic change(s)**

Create a new family, *Usuviridae*, with two genera for classification of viruses infecting human- and animal-gut-associated methanogenic archaea, and include this family in the existing order *Methanobavirales*.

**Justification**

Whole-proteome-based phylogenomic analysis using VipTree placed Methanobrevibacter smithii tailed virus 1-like viruses in a distinct clade, outside of the recently established families of tailed viruses associated with methanogenic archaea or other archaeal hosts.

**Submitted:** 21/06/2024; **Revised:** 11/09/2024

<table><caption>**Table 6.** *Usuviridae*, five new taxa*</caption><thead><tr><th>Operation</th><th>Rank</th><th>New taxon name</th><th>Virus name</th><th>Exemplar</th></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Usuviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Manusuvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Hewusuvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Manusuvirus methanobrevibacteri</td><td>Methanobrevibacter smithii tailed virus 1</td><td>PP537965</td></tr><tr><td>New taxon</td><td>Species</td><td>Hewusuvirus methanobrevibacteri</td><td>Methanobrevibacter gottschalkii virus vir075</td><td>BK068243</td></tr></tbody></table>

## 2024.007A.Eurekaviridae_newfam

**Title:** Create a new family, *Eurekaviridae*, of spindle-shaped archaeal virus

**Authors:** Coves M, Krupovic M, Bize A (ariane.bize@inrae.fr)

<footnote>*Source/full text: https://ictv.global/proposals/2024.005A.Bathyarchaeia_4newfam.zip</footnote>

<footnote>*Source/full text: https://ictv.global/proposals/2024.006A.Usuviridae_newfam.zip</footnote>
## Summary

### Taxonomic rank(s) affected

We suggest creating a new family, a new genus and a new species for classification of a spindle-shaped archaeal virus predicted to infect *Methanosarcina* species.

### Description of current taxonomy

Three families of small spindle-shaped archaeal viruses are currently defined: *Fuselloviridae*, *Halspiviridae* and *Thaspiviridae*. In addition, several spindle-shaped viruses are still unclassified. No spindle-shaped viruses infecting methanogenic archaea have been classified so far.

### Proposed taxonomic change(s)

We suggest creating a new family (*Eurekaviridae*), a new genus (*Hesperidvirus*) and a new species (*Hesperidvirus aureum*) to classify a newly sequenced uncultured virus, *Methanosarcina* spindle-shaped virus 1.

### Justification

The complete, circular *Methanosarcina* spindle-shaped virus 1 genome has been obtained through metavirome co-assembly, from samples collected in mesophilic anaerobic digestion batch microcosms fed with biowaste. This genome encodes two copies of the major coat protein similar to those of previously characterized spindle-shaped viruses. However, it does not show significant genomic similarity to other archaeal spindle-shaped viruses, which justifies the creation of a new family.

**Submitted:** 26/06/2024; **Revised:** 02/10/2024

<table><caption>**Table 7.** *Eurekaviridae*, three new taxa*</caption><thead><tr><td>Operation</td><td>Rank</td><td>New taxon name</td><td>Virus name</td><td>Exemplar</td></tr></thead><tbody><tr><td>New taxon</td><td>Family</td><td>Eurekaviridae</td><td></td><td></td></tr><tr><td>New taxon</td><td>Genus</td><td>Hesperidvirus</td><td></td><td></td></tr><tr><td>New taxon</td><td>Species</td><td>Hesperidvirus aureum</td><td>Methanosarcina spindle-shaped virus 1</td><td>PQ167755</td></tr></tbody></table>

**Author affiliations:** ¹Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, Paris, France; ²Université Paris-Saclay, INRAE, PROSE, Antony, France; ³Institut Pasteur, Université Paris Cité, CNRS UMR6047, Evolutionary Biology of the Microbial Cell, Paris, France; ⁴Institute for Advanced Study, Shenzhen University, Shenzhen, PR China; ⁵College of Food Science and Technology, Shanghai Ocean University, Shanghai, PR China; ⁶The Hong Kong University of Science and Technology, Hong Kong, PR China; ⁷Computational Biology Branch, Division of Intramural Research, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA; ⁸Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Australia; ⁹University of Innsbruck, Innsbruck, Austria; ¹⁰Entwicklungsgenetik und Zellbiologie der Tiere, Philipps-Universität Marburg, Marburg, Germany; ¹¹Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, PR China.

**Keywords:** Adrikavirales; Ageovirales; Agnivirus; Agnivirus brisbanense; Apasviridae; Aprofivirus; Aprofivirus guaymasense; Avenivirus; Avenivirus atlanticense; Baiafusivirus; Baiafusivirus chesapeakense; Baiafusivirus delawarense; Calorviricota; Caminiviricetes; Chiyouviridae; Dafengvirus; Dafengvirus linsing; Eurekaviridae; Fuxiviridae; Geogavirus; Geogavirus atlanticense; Geogavirus guaymasense; Geogavirus pacificense; Hesperidvirus; Hesperidvirus aureum; Hewusuvirus; Hewusuvirus methanobrevibacteri; Huangdiviridae; Krittikaviridae; Kunpengviridae; Manusvirus; Manusvirus methanobrevibacteri; Marefusivirus; Marefusivirus columbiaense; Marefusivirus helgoense; Marefusivirus jervisense; Marefusivirus montereyense; Marefusivirus pacificense; Nipumfusiviridae; Satyavativiridae; Taijivirus; Taijivirus yinyang; Terrafusivirus; Terrafusivirus michiganense; Terrafusivirus tennesseense; Thalassapleoviridae; Usuviridae; Velanvirus; Velanvirus brisbanense; Vyasavirus; Vyasavirus brisbanense; Wargodvirus; Wargodvirus xiongnu; Xuanyuanvirus; Xuanyuanvirus yandi; Yangshanfusivirus; Yangshanfusivirus mimetica.

**ICTV Taxonomy Summary Consortium:** Adriaenssens E.M.; Alfenas-Zerbini P.; Aylward F.O.; Freitas-Astúa J.; Hendrickson R.C.; Hughes H.R.; Kuhn J.H.; Lefkowitz E.J.; Lobocka M.; Mayne R.; Mushegian A.R.; Oksanen H.M.; Penzes J.; Reyes Muñoz A.; Robertson D.L.; Roux S.; Rubino L.; Sabanadzovic S.; Simmonds P.; Smith D.B.; Suzuki N.; Turner D.; Van Doorslaer K.; Varsani A.; Zerbini F.M.

## Funding Information

This work was partly supported by Agence Nationale de la Recherche, France (ANR-17-CE05-0011, project VIRAME to A.B.), by the doctoral school ABIES and by INSU/CNRS through the EC2CO program (project DEPICTO). E.V.K. is supported by the Intramural Research Program of the National Institutes of Health (National Library of Medicine). This work was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under Award No. U24A162625. H.M.O. was supported by the University of Helsinki and the Research Council of Finland by funding for FINStruct and Instruct Centre FI, part of Biocenter Finland and Instruct-ERIC and Horizon MSCA 101120407. This work was supported in part through Laulima Government Solutions, LLC prime contract with the U.S. National Institute of Allergy and Infectious Diseases under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services, a subcontractor of Laulima Government Solutions, LLC, under Contract No. HHSN272201800013C. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Health and Human Services or of the institutions and companies affiliated with the authors.

<footnote>*Source/full text: https://ictv.global/proposals/2024.007A.Eurekaviridae_newfam.zip</footnote>
Acknowledgements

This is a publication of the International Committee on Taxonomy of Viruses (ICTV), a non-profit, volunteer committee of the Virology Division of the International Union of Microbiology Societies (IUMS). The ICTV does not represent or endorse the views and actions of governments or the institutions or organisations for which its co-authors work.

Conflicts of interest

The authors declare no conflict of interest.

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