48 taxonomic novelties named June 10–11: a Triassic fossil with a 20-year cold case, 16 Moroccan spiders, and a record single-day count (2026)

Thursday June 10–11 produced 45 new species, 2 new genera, and 1 new status — the highest single-day yield recorded since this channel began tracking in June 2026. Three large monographs published simultaneously drove the number: Zootaxa 5830(1) (14 new Autolytinae polychaetes + a new genus from Australian waters), EJT 1067 (16 new Moroccan spiders), and PhytoKeys 276 (10 new Selaginella spike-mosses from northern South America). The day also delivered a Triassic archosauriform from Brazil whose holotype sat partially misplaced in a museum drawer for over two decades, and a deep-sea clam from Japanese cold seeps that broke a seven-day WoRMS dry streak.

Taxonomic spread: 17 Arachnida (16 spiders from Morocco, 1 from Turkey), 14 Annelida (Autolytinae polychaetes, Australia), 10 Lycopodiopsida (spike-mosses, northern South America), 2 Insecta (chironomid midges, China), 1 Bivalvia (thyasirid clam, Japan), 1 fossil archosauriform (Triassic, Brazil). All 45 extant species are Not Evaluated by IUCN, though the PhytoKeys article includes preliminary assessments: 6 of the 10 new spike-mosses are Critically Endangered, 3 are Endangered, and 1 is Vulnerable.

Fossil: a Triassic archosauriform with a 20-year cold case

Silescelida acristata Garcia, Cerqueira, Battista, Andrade & Müller gen. et sp. nov. is a new genus and species of early-diverging eucrocopodan archosauriform — the broader evolutionary grade that includes the ancestors of crocodylians, birds, and their kin — from the Middle Triassic (Ladinian stage, approximately 240 million years ago) of Rio Grande do Sul, southern Brazil. 1

Silescelida acristata Fig. 2 — bone photographs and interpretive drawings of the holotype left scapula, right ilium, and left femur (MCP 4186-PV) in multiple views — Holotype MCP 4186-PV bones in multiple views: the three preserved elements (scapula, ilium, femur) whose reunification enabled the genus description after the femur had been missing for over 20 years. 1

Holotype: MCP 4186-PV — a left scapula, right ilium, and left femur found in association at the Posto site, Dona Francisca municipality, Rio Grande do Sul. The specimen comes from the Pinheiros-Chiniquá Sequence of the Santa Maria Supersequence, Paraná Basin, and represents the first non-proterochampsian, non-archosaurian archosauriform from that stratigraphic unit.

The species carries a built-in mystery in its name: the genus name Silescelida combines Latin siles ("silence") with Greek skelēs ("hind leg"), a reference to the proximal femur that had gone missing from the collection for over 20 years. When the misplaced fragment bearing the collection code MCP 4186-PV was eventually rediscovered in the PUCRS (Pontifical Catholic University of Rio Grande do Sul) collection, it finally allowed the authors to complete a full morphological assessment. 1

The species epithet acristata (Latin: "without crest") names the key diagnostic character: the absence of an elevated mound or crest on the femur for attachment of the m. caudofemoralis — the muscle responsible for the tail-driven locomotion characteristic of many archosaur relatives. Phylogenetic analyses using implied weighting (k=23, 287 operational taxonomic units × 919 characters) recover Silescelida within Euparkeriidae or as a stem-eucrocopodan, though its exact position shifts depending on OTU composition. Authors are Josiel Garcia, Nathan S. Cerqueira, Geovane Battista, Marcus V. T. de Andrade (Universidade Federal de Santa Maria), and Marcel B. Müller (PUCRS).

Taxonomy: Animalia → Chordata → Reptilia (archosauriform grade) → Eucrocopia → Silescelida

Arachnida: 16 new spiders from Morocco, 1 from Turkey

The EJT 1067 Morocco monograph (16 species)

Sébastien Lecigne, Abdellah Moutaouakil, and Jean Lips (European Journal of Taxonomy issue 1067) sampled Morocco's spiders across eight caves in Tazekka National Park and the Beni Snassen massif, alongside coastal dunes, mixed forests, arid stony grasslands, and shrubby slopes, between 2021 and 2025. The monograph describes 16 new species across 11 genera and 6 families, and pushes Morocco's total spider checklist to 659 species, of which 197 (29.9%) are considered endemic. 2

Agelenidae — funnel-weavers (4 species)

Agelescape atlas Lecigne et al., sp. nov. — male only known; holotype ♂ from Azgour, Anoughal (Al-Haouz Province), High Atlas, 1,653 m; total body length 6.65 mm; carapace dorsally with 3 light longitudinal stripes; diagnostic tibial apophysis in two parts (dorsal + ventral branches); filamentous embolus running from 9 to 12 o'clock position. Provisionally placed in Agelescape; authors note the genus is poorly delimited. 2 Not Evaluated (IUCN).
Gorbiscape dayetchiker Lecigne et al., sp. nov. — male only; holotype ♂ from Bab Boudir, Tazekka NP, 1,270 m; total length 5.80 mm; named after Dayet Chiker lodge near Tazekka, where the team stayed during a biospeleology expedition; unique thick, broad conductor and S-shaped embolus with pointed anteriorly directed tip. 2 Not Evaluated.
Gorbiscape hichamelguerrouji Lecigne et al., sp. nov. — the largest Gorbiscape described in this paper; male 9.15 mm, female 10.40 mm; known from two mountainous localities roughly 530 km apart (Beni-Snassen at 430 m and the High Atlas at 2,330 m); named in tribute to Hicham El Guerrouj, Morocco's Olympic champion middle-distance runner. Authors write: "In naming this species, the first author wished to pay special tribute to one of the greatest athletic champions of all time." 2 Not Evaluated.
Gorbiscape littoralis Lecigne et al., sp. nov. — male only; holotype collected by pitfall trap behind Agadir beach in dune grassland, 22 m; total length 6.34 mm; uniquely among Gorbiscape species, patellar apophysis in two distinct parts (retrolateral + dorsal); embolus large, robust, and partially twisted. 2 Not Evaluated.
Lycosoides jlida Lecigne et al., sp. nov. (Agelenidae) — female only; holotype from Jlida 2 cave, Berkane, 542 m; total length 5.20 mm; classified as a troglophile (cave-associated but not an obligate cave-dweller); distinctive double-structure epigyne (triangle-like plates facing each other) and spermathecae elongated and inclined outward. Named after Jlida cave in the Beni-Snassen massif. 2 Not Evaluated.

Dysderidae — woodlouse spiders (2 species)

Dysdera asaahil Lecigne et al., sp. nov. — holotype ♂ from Bouarfaten, Nador Province; known from two coastal localities near the Moroccan-Algerian border; total length ♂ 6.00 mm, ♀ 9.10–9.70 mm; medium-sized, assigned to the D. crocata-complex; carapace and chelicerae dark orange in males, purplish in live females; name from Arabic asaahil (coastline). 2 Not Evaluated.
Dysdera sidimaafa Lecigne et al., sp. nov. — holotype ♂ from Sidi Mâafa peri-urban park, Oujda, 640 m; total length ♂ 6.80 mm, ♀ 8.80 mm; resembles D. crocata but differs in anterior femur spination (1–2 antero-apical spines present, vs. spineless in D. crocata) and in a lamellar process on the embolic division of the bulb. Named after the park. 2 Not Evaluated.

Gnaphosidae — ground spiders (6 species)

Berlandina campestris Lecigne & Moutaouakil, sp. nov. — female only; holotype from Gheba, Jaidate, 80 m; total length 9.40 mm; found by hand at the edge of a crop; resembles B. plumalis but epigyne fovea roughly 1.1× as wide as spermathecal span (vs. ≥1.3× in B. plumalis), and copulatory duct tips curved forward rather than directed laterally. 2 Not Evaluated.
Echemus amicitiae Lecigne, Moutaouakil & Lips, sp. nov. — both sexes known (5 males, 1 female); holotype ♂ from Ghiata Al Gharbia near Taza, 276 m; total length ♂ 5.50 mm; epithet amicitiae (Latin: "friendship"), reflecting the team's camaraderie; male distinguished by stair-step shaped inner margin of tibial apophysis; female by two large atria occupying nearly two-thirds of epigyne length. 2 Not Evaluated.
Nomisia tazekka Lecigne et al., sp. nov. — female only; holotype from Bab Boudir, Tazekka NP, 1,392 m; total length 6.15 mm; resembles N. palaestina but the atrium is roughly 2× wider at the base than at the front (vs. ~3× in N. palaestina), and the tubular spermathecal extension forms a loop rather than a recurved curve. Named for Tazekka National Park. 2 Not Evaluated.
Zelotes pax Lecigne & Moutaouakil, sp. nov. — both sexes; holotype ♂ from near Idriss I dam, Taounate Province, 216 m; total length ♂ 3.55 mm; epithet pax (Latin: "peace"), dedicated to hope for peace in Palestine, Ukraine, and other conflict regions — "an encouragement and a hope for lasting peace," the authors write. 2 Not Evaluated.
Zelotes rex Lecigne et al., sp. nov. — male only; holotype from Agadir beach, 22 m; total length 5.00 mm; name rex (Latin: "king") references the royal palace dunes of Agadir; unique hook-shaped median apophysis pointing ventrally combined with a trapezoid terminal apophysis directed antero-retrolaterally. 2 Not Evaluated.
Zelotes subcallidus Lecigne et al., sp. nov. — male only; known from two localities roughly 900 km apart (Agadir coast and Berkane Province); holotype 7.00 mm; resembles Z. callidus but retrolateral tibial apophysis tip bent and bifid, and prolateral projection of embolar base straight and tooth-like. 2 Not Evaluated.

Linyphiidae — sheet-weavers (1 species, troglobitic)

Lepthyphantes s. lat. ntafaghi Lecigne et al., sp. nov. — both sexes; holotype ♂ from Ifri N'Tafaghi cave, Aïn Sfa, Beni Snassen, 945 m; total length ♂ 1.94 mm; troglobitic (obligate cave-dweller); partially reduced eyes in some females; closely related to L. noeli from a cave 13 km away but differs in the lamella characteristica extending beyond the terminal apophysis (reversed in L. noeli) and female spermathecae coiling only 2 times (vs. 3). The two troglobitic congenera are separated by only 13 km of the Beni-Snassen limestone massif. 2 Not Evaluated.

Oecobiidae — wall spiders (2 species)

Oecobius diafa Lecigne & Lips, sp. nov. — male only; holotype from residual lapiaz near Séfrou, 527 m; 2.27 mm; name from Arabic diafa (hospitality); unique two-branched tegular apophysis with a short rounded finger-shaped outgrowth on the radical apophysis. 2 Not Evaluated.
Oecobius tiznit Lecigne et al., sp. nov. — male only; holotype from under limestone behind Aglou beach near Tiznit, 26 m; 2.20 mm; distinguished from all congeners by a complex two-part tegular apophysis connected by a strongly sclerotized sub-horizontal structure; also two-branched radical apophysis. Named after Tiznit Beach. 2 Not Evaluated.

Zodarion new species from Turkey

A new species of Zodarion Walckenaer (Araneae: Zodariidae — ant-eating spiders) was described from Turkey by İlhan Coşar, Tarık Danışman, and Ersen Aydın Yağmur, published online June 10, 2026 in the Journal of Natural History. 3 Turkey's Zodariidae currently comprises 37 species in four genera, with 34 assigned to Zodarion; detailed morphological description is behind a paywall and not reproduced here. Not Evaluated (IUCN).

Taxonomy (all Morocco species + Turkey): Animalia → Arthropoda → Arachnida → Araneae

Annelida: 14 new polychaetes and a new genus from Australian waters

Zootaxa 5830(1) published an 85-page monograph on the subfamily Autolytinae (Annelida: Syllidae) from Australia — the first comprehensive revision of this group in Australian waters. 4 The study describes 14 new species and 1 new genus across 8 genera, and records three genera — Imajimaea Nygren, 2004, Epigamia, and Paraproceraea Nygren, 2004 — in Australian waters for the first time. Holotypes are deposited at the Australian Museum, Sydney. Authors used scanning electron microscopy on the most abundant taxa and documented reproductive stolons (the free-swimming sexual reproductive stages distinctive to Autolytinae) for several species.

Zootaxa 5830(1) cover: Autolytinae polychaete specimen with yellow dorsal midline and blue-violet parapodia against black background — *Zootaxa* 5830(1) cover specimen — one of the 14 new Autolytinae polychaetes from Australia. 4

New genus: Nygrenia gen. nov. — named after Arne Nygren, author of the 2004 foundational revision of Autolytinae (Zootaxa 680); this is the first new Autolytinae genus erected since that revision. Contains two new Australian species: 4

The 14 new species, with notes on diagnostic epithets where inferable from the abstract-level data available:

Species	Genus	Key epithet note
Nygrenia acutidentata sp. nov.	Nygrenia gen. nov.	acutidentata = "sharply toothed"
Nygrenia longiproventriculata sp. nov.	Nygrenia gen. nov.	refers to an elongated proventricle, a key Syllidae foregut structure
Imajimaea annulata sp. nov.	Imajimaea	first Imajimaea described from Australia
Imajimaea gerardoi sp. nov.	Imajimaea	named for a colleague or collector (full etymology paywalled)
Paraproceraea duplotransversa sp. nov.	Paraproceraea	"doubled transverse" — morphological marking
Paraproceraea garciabarrosi sp. nov.	Paraproceraea	named for a contributor (García Barros)
Paraproceraea tricolor sp. nov.	Paraproceraea	three-color body pigmentation
Paraproceraea werrup sp. nov.	Paraproceraea	likely from an Australian Aboriginal word
Proceraea australis sp. nov.	Proceraea	australis = "southern" (Australia)
Proceraea boolajimbirn sp. nov.	Proceraea	likely from an Aboriginal language
Proceraea nuriae sp. nov.	Proceraea	named for a person (Nuria)
Proceraea orangeotransversa sp. nov.	Proceraea	orange transverse body marking
Myrianida polocaviae sp. nov.	Myrianida	full etymology paywalled
Myrianida pharyngeolongissima sp. nov.	Myrianida	"longest pharynx" — an unusually elongated pharyngeal structure

All species Not Evaluated (IUCN). Detailed morphological descriptions and diagnostic characters are behind the Zootaxa paywall; the abstract confirms all 14 species and genus-level placements. Taxonomy: Animalia → Annelida → Polychaeta → Phyllodocida → Syllidae → Autolytinae

Plants: 10 new spike-mosses from northern South America (plus 1 status change)

Iván A. Valdespino (Universidad de Panamá / Smithsonian Tropical Research Institute), Christian A. López (University of Texas at Austin / STRI), and Julián Mostacero Giannangeli (Universidad Nacional de Trujillo) published 10 new species of Selaginella (Lycopodiopsida: Selaginellaceae) in PhytoKeys 276, drawn primarily from Venezuela with extensions into Colombia. 5 The paper also elevates one variety to species rank and provides distributional updates. All figures are CC BY 4.0. Six of the 10 new species carry IUCN Critically Endangered preliminary assessments, 3 are Endangered, and 1 is Vulnerable — reflecting the narrow endemic distributions and threatened habitats across the northern Andes and Guayana Highlands.

Selaginella turingiana Valdespino holotype (NYBG No. 87098, New York Botanical Garden), collected J.A. Steyermark, September 11, 1960, Miranda State, Venezuela — Holotype of *Selaginella turingiana* Valdespino sp. nov. (NYBG), collected 1960 and formally named 2026 after Alan Turing. 5

Taxonomy (all 10): Plantae → Lycopodiophyta → Lycopodiopsida → Selaginellales → Selaginellaceae → Selaginella

Species	Authority	Locality	Elevation (m)	IUCN preliminary
S. cataniapensis	Valdespino	Venezuela, Cataniapo R. basin, Amazonas/Bolívar	90–600	EN
S. cultellifolia	Valdespino & C.López	Colombia (Boyacá) + Venezuela (Barinas)	1300–2500	CR
S. guaramacalensis	Valdespino & C.López	Venezuela, Guaramacal NP, Trujillo/Portuguesa	1000–1950	EN
S. liesneri	Valdespino	Venezuela, Cerro de la Neblina, 1 specimen known	1250	CR
S. mawarinumensis	Valdespino & C.López	Venezuela, Mawarinuma River, EOO 0.860 km²	140–170	CR
S. monoloba	A.R.Sm. ex C.López, Valdespino & Mostacero	Colombia (Cesar/Magdalena) + Venezuela (Miranda)	500–1600	EN
S. mostaceroi	Valdespino & C.López	Venezuela, Táchira, 1 specimen known	600–1000	CR
S. plagiochiloides	Valdespino & C.López	Venezuela, Neblina Base Camp, 3–7 cm plant	150	CR
S. tricula	A.R.Sm. ex Valdespino & C.López	Venezuela, Barinas; no spores found	900	CR
S. turingiana	Valdespino	Venezuela, coastal ranges, 4 states	400–1219	VU

Selected morphological highlights:

Selaginella turingiana is the widest-ranging of the ten, known from four Venezuelan coastal-range states (Aragua, La Guaira, Miranda, Yaracuy). Its lateral leaves rise steeply alongside the main stem, nearly parallel to it up to the 9th branching point — an arrangement unusual in a genus of roughly 750 species. Valdespino named it after Alan M. Turing (1912–1954) to honor Turing's contributions to theoretical biology, including his mathematical model relating phyllotaxis (leaf arrangement) to Fibonacci sequences. The paper quotes Turing: "We can see only a short distance ahead, but we can see plenty there that needs to be done." The species' discovery also resolves a longstanding misidentification: specimens from the Venezuelan coastal ranges previously assigned to S. anceps are now formally attributed to S. turingiana. 5 Not Evaluated (global IUCN); preliminary assessment: VU.

Selaginella plagiochiloides is a minute rock-dwelling plant, crawling stems just 3–7 cm long, whose leaf shape is so reminiscent of the liverwort genus Plagiochila that the species was named for the resemblance. The paper records — for the first time in a Neotropical Selaginella — occasional bifid (split-tipped) leaves in the lateral series, a feature previously documented only in the Old World species S. helvetica. Valdespino and López caution this bifid condition is sporadic and may reflect developmental variability rather than a stable taxonomic character. 5 Preliminary assessment: CR (AOO 4 km²).

Selaginella tricula is exceptional for a different reason: no sporangia, spore-bearing leaves, or spores were found on any of the known specimens. The plant grows on waterfall cliffs and shaded sandstone at 900 m in Barinas; Valdespino and López suggest the collected material may have been gathered outside the reproductive season, or the species may rely primarily on vegetative reproduction. 5 Preliminary assessment: CR.

Selaginella mawarinumensis, at 140–170 m along the banks of the Río Mawarinuma near Neblina Base Camp, carries the smallest known extent of occurrence among the ten new species: 0.860 km² — among the most geographically restricted spike-mosses yet documented. 5 Preliminary assessment: CR.

Selaginella monoloba (published from a manuscript by Alan R. Smith, formalized here by López, Valdespino & Mostacero) is notable structurally: its median leaves are peltate (shield-attached at their centers rather than at their bases), a feature rare in the articulate-stemmed Selaginella species, and each spike bears only one macrosporangium — unusual across the S. horizontalis species complex, where multiple macrosporangia are the rule. 5 Preliminary assessment: EN (EOO 37 km²).

Status change (not a new species): Selaginella anemosyra Valdespino nom. et stat. nov. is elevated from variety rank (S. flabellata var. latifrons A.Braun, 1865) to full species status. The Venezuelan coastal plant had already been recognized informally as a distinct species by Alston in 1938, but the name was never formally published. It differs from S. flabellata in its fan-shaped (vs. pinnate) branching outline and wider lateral leaves (10–19 mm across the stem vs. 4–8 mm). Preliminary assessment: EN. 5

Insects: two cryptic midges from the Yarlung Zangbo canyon

Yi-Zhu Chen, Xiao-Long Lin (Shanghai Ocean University), Zhi-Chao Zhang, Yan Zhang, and Tenzin Nyima (Institute of Plateau Biology of Xizang) described two new chironomid midges (Diptera: Chironomidae: Orthocladiinae) from Medog (Motuo) County, Xizang Autonomous Region, China, using DNA barcodes to distinguish them within the formerly lumped Cricotopus montanus species group. 6 The paper amends the subgenus diagnosis and provides a key to all known adult males of Cricotopus (Pseudocricotopus); before this study, the subgenus contained only 7 described species worldwide. 7

Cricotopus (Pseudocricotopus) motuoensis Chen & Lin, sp. nov. — named after Motuo (Medog), the county at the center of the Yarlung Zangbo Grand Canyon National Nature Reserve. Lin Xiaolong (associate professor, Shanghai Ocean University) stated: "The discoveries further highlight the ecological significance of Medog and the Yarlung Zangbo Grand Canyon National Nature Reserve, a globally recognized biodiversity hotspot." 7 Detailed morphological description in the paywalled paper. Not Evaluated (IUCN).
Cricotopus (Pseudocricotopus) neomatudigitatus Chen & Lin, sp. nov. — second cryptic species from the same C. montanus complex, same study area. Not Evaluated (IUCN).

Taxonomy: Animalia → Arthropoda → Insecta → Diptera → Chironomidae → Orthocladiinae → Cricotopus

Bivalvia: a new cold-seep clam from Japan, named for a taxonomist

Thyasira okutanii Amano, H. Watanabe & C. Chen, 2026 sp. nov. (Mollusca: Bivalvia: Lucinida: Thyasiridae) was registered in WoRMS on June 10, 2026 (AphiaID: 1895897), ending a seven-consecutive-day gap in marine species registrations tracked by this channel. 8 The formal description appeared in The Nautilus 140(2): 41–50.

Type locality: Ryuyo Canyon cold seep, 34°12'04" N, 137°45'39" E, at 1,099 m depth, off Shizuoka Prefecture, central Japan. Additional material from two further Nankai Trough and Sagami Bay cold seeps (1,189–1,495 m depth). Specimens were collected by the Shinkai 6500 human-occupied vehicle during JAMSTEC cruises between 2021 and 2025; type specimens are deposited at the National Museum of Nature and Science, Tsukuba (NSMT-Mo). 9

The species carries a very shallow and wide posterior sulcus with a slight posterior sinus, a radial furrow forming a blunt ridge, and a distinctly depressed lunule demarcated by a groove — features that collectively distinguish it from all other Thyasira in the region. 9 Morphologically closest to T. sarsi (Philippi, 1845) from the North Atlantic and Arctic — a relationship supported by 18S rRNA gene data, though COI phylogeny places T. okutanii as sister to all other thyasirids with available sequences (albeit with low statistical support). Like other thyasirids, the species hosts chemoautotrophic bacteria in its gills, deriving nutrition from the hydrogen sulfide and methane seeping through the Nankai Trough subduction zone seafloor.

Named for the late Emeritus Professor Takashi Okutani (JAMSTEC), who contributed extensively to Thyasira taxonomy in Japanese waters. Japanese vernacular name: Okutani-hanashi-gai. Authors: Kazutaka Amano (Joetsu University of Education), Hiromi Kayama Watanabe, and Chong Chen (JAMSTEC). GenBank accessions: COI PX697597, 18S PX697246. 9

Not Evaluated (IUCN). Taxonomy: Animalia → Mollusca → Bivalvia → Lucinida → Thyasiridae → Thyasira

Context: 149 marine species catalogued from Indian Ocean seamounts (not formally described)

A synthesis paper published in Deep Sea Research Part II Vol. 227 by Timothy D. O'Hara et al. (Museums Victoria / CSIRO) reported 1,059 operational taxonomic units from 22 seamounts, two island groups, and the abyssal plain around Christmas and Cocos (Keeling) Islands, of which 149 (14%) were identified as new to science. 10 11 These 149 entities are catalogued as operational taxonomic units in a community-ecology study, not individually formally described in this paper; their formal species descriptions exist or are pending in separate companion taxonomic publications. They are not counted in today's 45 formally described species.

The two RV Investigator voyages (2021–2022) sampled depths from 94 to 5,431 m. Decapods and fishes accounted for the most species; ophiuroids (brittle stars) were the most abundant organisms. Dr Elena Kupriyanova (deep-sea worm researcher) described seamounts as "stepping stones" that allow deep-sea organisms to move between ecosystems. The paper is covered separately as context for the broader biodiversity survey.

Sources

All 45 formally described species reported above are from sources published within the June 10, 17:27 UTC – June 11, 16:00 UTC window. The Scorpiones paper from Journal of Natural History (Nehbandan County, Iran) was published June 9 — one day before the window — and is not counted. The CSIRO Indian Ocean seamounts paper documents operational taxonomic units, not formal species descriptions, and is noted above as contextual.

Cover image: Silescelida acristata gen. et sp. nov. — holotype overview figure including fossil locality map, outcrop photograph, specimen, and skeletal silhouette. 1