taxonID	type	description	language	source
5C6887BDCA52775A9C7DFE1AFAEBFB62.taxon	type_taxon	Type species Asclerocheilus intermedius (Saint-Joseph, 1894).	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA52775A9C7DFE1AFAEBFB62.taxon	diagnosis	Diagnosis Body elongate, arenicoliform. Prostomium T-shaped with frontal horns. Parapodia of posterior segments reduced; dorsal and ventral cirri absent; interramal papillae or cilia present or absent; postchaetal lamellae absent. Branchiae absent. Chaetae include capillaries, furcate chaetae, and large, conspicuous curved spines on setigers 1 to 4, sometimes accompanied by short spinous setae. Pygidium with long anal cirri.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA52775A9C7DFE1AFAEBFB62.taxon	discussion	Remarks The genus was erected by Ashworth (1901), to include the species A. intermedius (Saint-Joseph, 1894), previously assigned to the genus Lipobranchius Cunningham & Ramage, 1888. In the same work, Ashworth (1901) differentiated Asclerocheilus from Sclerocheilus Grube, 1863 by the absence of parapodial cirri, positioning the genus within the family subgroup I, containing species with an “ arenicoliform ” body shape. Subsequently, several new species were described. Blake (1981) transferred S. acirratus Hartman, 1966 to Asclerocheilus acirratus (Hartman, 1966) and presented two new species to the genus. Hartmann-Schröder (1994) compared the known species, providing important information on their morphological differences. Blake (2000) referred Kebuita glabra (Ehlers, 1887) to Asclerocheilus glabrus (Ehlers, 1887). The author also followed Hartman's (1938) synonymization of Gwasitoa Chamberlin, 1919 with Kebuita Chamberlin, 1919, and synonymized Kebuita with Asclerocheilus. Moreover, Blake (2000) erected A. victoriensis Blake, 2000 as a new name to replace A. heterochaetus Kudenov & Blake, 1978. This was proposed because Oncoscolex heterochaetus is a synonym of Kebuita glabra (Ehlers, 1887), and K. glabra was transferred to A. glabrus within the same work. In this sense, A. heterochaetus consequently is a junior homonym of O. heterochaetus. Thus, Blake (2000) renamed the homonym A. victoriensis (Hartman 1938; Blake 2000, 2023). Finally, Blake (2023) published the most recent advances on the genus taxonomy and ecology, transferring Oligobregma tasmania to A. tasmanius and describing an abyssal species from Australia. Currently, the genus Asclerocheilus counts 15 described species, they are A. glabrus (Ehlers, 1887), from the Caribbean Sea; A. intermedius (Saint-Joseph, 1894) from the eastern North Atlantic; A. beringianus Ushakov, 1955 from the Bering Sea; A. capensis Day, 1963 from South Africa; A. californicus Hartman, 1963 from Southern California; A. acirratus (Hartman, 1966) from California; A. ashworthi Blake, 1981 from the Southern Ocean in Sub-Antarctic waters; A. tropicus Blake, 1981 from Ecuador; A. mexicanus Kudenov, 1985 from the Gulf of Mexico; A. shanei Hartmann-Schröder, 1994 from Tasmania; A. kudenovi Blake, 2000 from Central California; A. victoriensis Blake, 2000 from Southeast Australia; A. elisabethae Eibye-Jacobsen, 2002 from the Andaman Sea, Thailand; A. shanonae Eibye-Jacobsen, 2002 from the Andaman Sea, Thailand and A. abyssalis Blake, 2023 from Eastern Australia. Regarding the Brazilian coast, possible occurrences may be related to the species described in the following works: Day (1963, 1967), Blake (1981) and Kudenov (1985). Asclerocheilus tropicus is the only known species of Asclerocheilus found in Brazil, having been redescribed by Nogueira (2002). The material was sampled from Laje de Santos (24 ° 19 ′ S, 46 ° 11 ′ W), on 17 March 1996, and Ilha dos Alcatrazes (26 ° 06 ′ S, 45 ° 42 ′ W), on 4 December 1996; both localities are rocky shores with large colonies of cnidarians, from which the scalibregmatids were sorted (Nogueira 2002). Moreover, Nogueira (2002) provided an important account on the character variability within the species, such as the horns and prostomium shape, presence or absence of eyes as well as its colour and shape, the acicular spines shape, and the ratio of lyrate chaetae tynes. The latter account is important, because it provided important arguments regarding the validity of this character to separate species, firstly proposed by Blake (1981).	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	description	Figs 1 – 3	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	diagnosis	Diagnosis Triangular prostomium, with two long horns, both thin and projected upwards. Eyes absent. Ventral groove present from chaetiger 1 with first pad asymmetrically rounded, contributing to mouth’s lower lip formation. Acicular spines present on chaetigers 1 – 3 on notopodia, and 1 – 2 on neuropodia. Short spinous chaetae not observed. Lyrate chaetae present from chaetiger 2 on neuropodia and 3 on notopodia. Anterior chaetigers parapodial lobes larger, more prominent, present as broad blunted projection in both noto- and neuropodia. Pygidium present as short uniannulated segment, with crenulated margin.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	etymology	Etymology The specific epithet ‘ geiseae ’ was chosen to honour the Brazilian mastozoologist Dr Lena Geise, from the Rio de Janeiro State University (UERJ), for her important contributions to Brazilian zoology and to celebrate our friendship.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	materials_examined	Type material Holotype BRAZIL – Espírito Santo, Espírito Santo Basin • complete spec.; 19.959 ° S, 39.892 ° W; depth 11 m; Dec. 2010; van Veen grab; subtidal zone; UERJ, UERJ- 8065. Paratypes BRAZIL – Espírito Santo, Espírito Santo Basin • 1 complete spec., 1 incomplete spec.; 19.960 ° S, 39.892 ° W; depth 11 m; Dec. 2010; van Veen grab; subtidal zone; UERJ, UERJ- 8066 • 1 complete spec.; 19.9590 ° S, 39.893 ° W; depth 47 m; Jul. 2011; van Veen grab; subtidal zone; UERJ, UERJ- 8067 • 1 complete spec.; 19.959 ° S, 39.892 ° W; depth 47 m; Dec. 2010; van Veen grab; subtidal zone; UERJ, UERJ- 9223 • 1 complete spec.; 19.959 ° S, 39.892 ° W; depth 47 m; Dec. 2010; van Veen grab; subtidal zone; UERJ, UERJ- 9224.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	description	Description Holotype complete, 10 mm long, 1 mm wide over expanded region, 0.3 mm wide on narrowest region for 57 chaetigers. Medium-sized species, paratypes measuring 4 – 5 mm long, 0.4 – 0.6 mm wide expanded on anterior region, 0.13 – 0.25 mm wide on narrowest posterior region, for 32 – 44 chaetigerous segments. Body arenicoliform, weakly expanded over chaetigers 2 – 19. Colour in alcohol pale tan. Body surface covered by secondarily annulated rings. Secondary annuli composed by rounded to rectangular small pads, basally fused to each other, in both anterior and posterior regions. Annuli’s small pads on anterior region may be weaker in comparison to posterior region. Internal glands were not observed. Triangular prostomium, with two long horns, both thin and projected upwards (Figs 1 A – B, 2 B, 3 A – B). Eyes absent. Nuchal organs not observed. Peristomium achaetous, uniannulated in holotype, but some paratypes presented a peristomium biannulated ventrally and uniannulated dorsally. Proboscis smooth. Mouth’s lips presenting single row of paired lobes formed superiorly by peristomium and inferiorly by ventral groove first pad. Upper lip presents 5 – 6 lobules, lower lip presents 5 – 7 lobules. Ventral groove present from chaetiger 1 with first pad asymmetrically rounded, contributing to mouth’s lower lip formation on its superior margin (Figs 1 A – B, 3 A – B). Quadrangular bi- to triannulated pads present from chaetiger 2, forming ventral mid-ridge up to end of the body. Each pad is paired to a single chaetiger. Posterior pads thinner than anterior ones. Dorsally, chaetiger 1 with two secondary annuli connected to parapodial lobe, plus an intermediate annulation between chaetigers (Figs 1 A – B, 3 A – B); following chaetigers with three secondary annuli connected to parapodial lobe, and an intermediate annulation between chaetigers (Fig. 2 A, D). Ventrally, chaetigers 1 – 4 with two secondary annuli connected to parapodial lobes, plus an intermediate annulation between chaetigers (Figs 1 A – B, 3 A – B). Following chaetigers on anterior region with three secondary annuli connected to parapodial lobe, and also an intermediate annulation between chaetigers (Fig. 3 A). First and second chaetigers often smooth, but this variation should be interpreted as artefact. Interramal papillae rounded, present from anterior chaetigers (Fig. 2 A), smaller and sometimes absent in posterior chaetigers (Fig. 2 D), internal content unknown. Acicular spines present on chaetigers 1 – 3 on notopodia, and 1 – 2 on neuropodia (Figs 1 C – D, 2 B – C, 3 C). Short spinous chaetae not observed. Lyrate chaetae present from chaetiger 2 on neuropodia and 3 on notopodia (Figs 1 E, 2 E, 3 D), numbering 5 – 6 lyrate chaetae per fascicle, with unequal tynes (tynes ratio: 2.5 on anterior chaetigers to 1.8 – 2.22 on midbody to posterior chaetigers). Notopodial acicular chaetae organized in two rows on chaetigers 1 – 2, numbering up to 9 per row, with rounded tips (Figs 1 C, 2 B, 3 C). Notopodial acicular chaetae on chaetiger 3 organized in single row, numbering 5 transitional acicular spines, with pointed tips. Neuropodial acicular spines weaker than notopodial ones, organized in single row on chaetigers 1 – 2, all curved with pointed tips (Figs 1 D, 2 C), numbering 8 per fascicle, transitional on chaetiger 2. Capillaries organised in single row on chaetigers 1 – 2, then in two rows on chaetiger 4 up to middle of body. In posterior chaetigers, capillaries become organized in single row. Anterior chaetigers parapodial lobes larger, more prominent, present as broad blunted projection in both noto- and neuropodia, more robust and distinct than on posterior chaetigers (Fig. 2 A). Parapodial lobes becoming gradually thinner and smaller in midbody and posterior chaetigers, emerging as apically rounded projections (Fig. 2 D). Pygidium present as short uniannulated segment, with crenulated margin, from which emerges 4 long anal cirri; two dorso-lateral and two ventro-lateral (Fig. 3 E).	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	discussion	Remarks This species is morphologically similar to A. intermedius, A. shanei, A. abyssalis and A. blakei sp. nov. by having acicular spines on notopodia of chaetigers 1 – 3. However, it is unique among them by the presence of acicular spines with rounded tips in two rows on notopodia of chaetigers 1 – 2, then replaced by one row of acicular spines with pointed tips on notopodia of chaetiger 3. Moreover, A. abyssalis is the only species of the genus with short spinous chaetae mentioned on its description.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5577429C16FD7BFD74F8D8.taxon	biology_ecology	Ecology This species was found at the Rio Doce river mouth near the Campos Basin (Brazilian southern region), living on sandy sediment at depths of 11 – 50 m.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	description	Figs 4 – 6	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	diagnosis	Diagnosis Trapezoidal prostomium, with two long horns, both thin and projected laterally with inconspicuous aperture at their basis. Ventral groove present from chaetiger 1 with first pad asymmetrically rounded, bearing up to 4 small lobules on its superior margin, contributing to mouth’s lower lip formation. Acicular chaetae with pointed tips present in chaetigers 1 – 3 on notopodia and neuropodia. Lyrate chaetae from chaetiger 3 on notopodia and 2 on neuropodia, with unequal tynes. Pygidium present as short crenulated margin with up to 10 small lobes, from which emerges 6 long anal cirri.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	etymology	Etymology The specific epithet ‘ blakei ’ was chosen to honour Dr James A. Blake, for his important contributions to polychaete taxonomy, ecology and evolution. Most of the taxonomical issues concerning the family Scalibregmatidae were solved from his contributions, especially on the genus Asclerocheilus, which was revised by him (Blake 2000). The author also contributed to the second attempt to delimitate the genera within the family (Kudenov & Blake 1978), in the first work on species from the South Atlantic (Blake 1981), and in the first work describing the ontogeny and development of a scalibregmatid species (Blake 2015).	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	materials_examined	Type material Holotype BRAZIL • complete spec.; Rio de Janeiro, Campos Basin; 23.654317 ° S, 41.310094 ° W; depth 693 m; Jun. 2008; box corer; continental slope; UERJ, UERJ- 1133. Paratypes BRAZIL • 2 complete specs; Rio de Janeiro, Campos Basin; 21.186 ° S, 40.216 ° W; depth 683 m; Feb. 2009; box corer; continental slope; UERJ, UERJ- 6297 • 1 complete spec.; Espírito Santo, Espírito Santo Basin; 19.970 ° S, 39.519 ° W; depth 1908 m; Jun. 2013; box corer; continental slope; UERJ, UERJ- 9222.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	description	Description Holotype complete, 5 mm long, 1 mm wide over expanded region, 0.25 mm wide on narrowest region, for 36 chaetigerous segments. Moderate-sized species, paratypes measuring 6 – 13 mm long to 0.15 – 2 mm wide for 33 – 43 chaetigerous segments. Body arenicoliform, weakly expanded over chaetiger 8 – 7. Colour in alcohol pale tan to yellowish. Body surface covered by secondarily annulated rings in well preserved specimens. Secondary annuli composed by rounded to quadrangular small pads in both anterior and posterior regions. Annuli’s small pads on anterior region may be weaker in comparison to posterior region. Internal glands not observed. Trapezoidal prostomium, with two long horns, both thin and projected laterally (Figs 4 A – B, 5 A, 6 A). One pair of small eyespots on middle of prostomium in small specimens, but absent in adults. Nuchal organs not observed. Proboscis smooth. Peristomium achaetous, uniannulated dorsally (Figs 4 A, 6 A) and biannulated ventrally (Figs 4 B, 5 A), contributing to mouth’s upper lip formation. Ventral groove present from chaetiger 1 (Fig. 4 B) with first pad asymmetrically rounded, bearing up to 4 small lobules on its superior margin, contributing to mouth’s lower lips formation. Rectangular triannulated pads present from chaetiger 2, forming ventral mid-ridge up to end of body. Each pad paired to single chaetiger. Posterior pads thinner than anterior ones. Body chaetigers 1 – 2 with two secondary annuli connected to parapodial lobe, in addition intermediate annulation between chaetigers (Fig. 4 A – B). From chaetiger 3, three secondary annuli connected directly to parapodial lobe, in addition intermediate annulation between chaetigers (Figs 4 A – B, 5 E). Interramal papillae present, but inconspicuous on anterior and midbody chaetigers, emerging as blunted projection between noto- and neuropodial lobes on posterior chaetigers (Fig. 5 F). Acicular chaetae with pointed tips present in chaetigers 1 – 3 on notopodia and neuropodia (Figs 4 C, 5 C – D, 6 B – D). Lyrate chaetae with unequal tynes (tynes ratio 2.125), present in a single row from chaetiger 3 in notopodia and from chaetiger 2 in neuropodia (Figs 4 D, 5 B, 6 C); numbering 3 – 4 chaetae in both rami on anterior chaetigers, up to 8 in midbody chaetigers, then 4 – 5 in posterior chaetigers. Short spinous chaetae absent. Notopodial acicular spines organized in two rows on chaetigers 1 – 2, numbering 6 – 7 in anterior row and 8 – 9 in posterior row (Figs 4 C, 5 C – D, 6 B). Notopodial acicular spines on chaetiger 3 organized in single row of 8 transitional acicular spines (Fig. 6 D), with one row replaced by lyrate chaetae. Neuropodial acicular spines present on chaetigers 1 – 3, weaker than notopodial ones, organized in single row, numbering 5 per fascicle, being accompanied by anterior row of lyrate chaetae on chaetiger 2. Notopodial capillaries present in one row on chaetigers 1 – 2; then in two rows on chaetiger 3, then in three rows on chaetiger 4. Neuropodial capillaries organized in two rows in chaetigers 1 – 3, then in three rows on chaetiger 4. Noto- and neuropodia on posterior chaetigers with two rows of capillaries, then in single row on last 5 – 10 chaetigers. Smaller specimens present more posterior chaetigers with single row of capillaries. Notopodial and neuropodial capillaries longer on anterior body, up to chaetiger 8, giving spinous appearance. Parapodial lobes always asymmetrical, emerging as short and inconspicuous basis ending in rounded tip on anterior chaetigers, forming ‘ hill-like’ structure; on midbody chaetigers, parapodial lobes inflate at their basis, transitioning abruptly to pointed tip; on posterior most chaetigers, parapodial lobes become smaller and thinner, emerging as thin basis transitioning smoothly to pointed tip (Fig. 5 F). Pygidium present as short crenulated margin with up to 10 small lobes, from which emerges 6 long anal cirri (Figs 5 F, 6 E).	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	discussion	Remarks This species is morphologically similar to A. intermedius, A. shanei, A. abyssalis and A. geiseae sp. nov. by having acicular spines on notopodia of chaetigers 1 – 3. However, it is set apart from A. abyssalis by the absence of short spinous chaetae on noto- and neuropodia of chaetiger 3. Asclerocheilus shanei differs from A. blakei sp. nov. by the absence of capillaries following the acicular spines on chaetigers 1 – 3. Asclerocheilus intermedius differs from A. blakei by presenting lyrate chaetae fron chaetiger 4. Asclerocheilus blakei presents a single type of acicular spine on its chaetigers; they are curved with pointed tips, differing from A. geiseae spines, that end in blunt tips. Finally, both species have different prostomial and peristomial morphologies, being triangular with horns directed upwards in A. geiseae, whereas in A. blakei the prostomium is rounded to trapezoidal and its horns are thinner and laterally directed.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5877479C2FFEEEFC6FFA0D.taxon	biology_ecology	Ecology This species was found living on the continental shelf and slope of the Espírito Santo and Campos basins (Brazilian southern region), from a bathymetric range of 683 – 2900 m.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5C77459C09F9F6FD81FCC8.taxon	description	Fig. 7	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5C77459C09F9F6FD81FCC8.taxon	materials_examined	Material examined BRAZIL – Espírito Santo, Espírito Santo Basin • 1 incomplete spec.; 19.765 ° S, 39.507 ° W; depth 150 m; Jan. 2012; box corer; continental slope; UERJ- 9244 • 2 complete specs; 19.601 ° S, 39.176 ° W; depth 143 m; Jun. 2013; van Veen grab; continental slope; UERJ, UERJ- 4622.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5C77459C09F9F6FD81FCC8.taxon	description	Description Medium- to small-sized specimens; 3.5 – 5 mm long, 0.1 – 0.5 mm wide for 13 – 34 chaetigers. Prostomium with two large flaring lobes (Fig. 7 A – B). When present, eyes as broad obliquely longitudinal lines, with orange coloration, positioned near posterior margin of prostomium. Peristomium uniannulated, smooth. First chaetigers biannulated; then tri- to quadriannulated from midbody to posterior chaetigers. Acicular spines on notopodia of chaetiger 1, numbering 5 – 6, present in two rows (Fig. 7 C). Short spinous chaetae absent. Lyrate chaetae from chaetiger 2 (Fig. 7 D), with unequal tynes (tynes ratio = 1.8 – 2.1), present in single row anterior to capillaries, numbering 3 – 5. Capillaries organized in two rows on anterior to midbody chaetigers then in single row on posterior chaetigers. Two specimens lack posterior end, but one presented short pygidial margin, without cirri.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5C77459C09F9F6FD81FCC8.taxon	discussion	Remarks The specimens collected during the research campaigns material agree in their morphological and ecological features those described by Blake (1981) and Nogueira (2002). Importantly, Nogueira (2002) confirmed his identifications comparing the Brazilian specimens with type material of A. tropicus. Here, we expand the distribution of the species to the Espírito Santo and Campos basins. Interestingly, the variation regarding the presence of a sulcus separating the prostomial lobes was also observed in some specimens, with the prostomium lacking a clear separation from them, even under staining (Fig. 7 A – B). On the other hand, the number of acicular spines (Fig. 7 C) and lyrate chaetae (Fig. 7 D) did not reach the maximum number reported by Nogueira (2002) but agreed in overall shape. Regarding the body annulation, most specimens were in poor state, hampering a clear distinction of secondary annuli in most chaetigers. In the light of the abovementioned considerations, the specimens did not present enough variability to justify their separation from A. tropicus sensu Nogueira (2002). Further studies exploring the identity of this species using molecular data are needed, considering its Pacific and South Atlantic records, both confirmed by morphology.	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
5C6887BDCA5C77459C09F9F6FD81FCC8.taxon	biology_ecology	Ecology We found specimens living on the continental shelf of the Espírito Santo and Campos basins, in a bathymetric range up to 157 m deep. This find is relevant, because we expand its bathymetric distribution, considering the previous accounts based on records of specimens living in shallow subtidal waters (Blake 1981; Nogueira 2002).	en	Mendes, Samuel Lucas Da Silva Delgado, Paiva, Paulo Cesar De, Rizzo, Alexandra E. (2024): On species of Asclerocheilus Ashworth, 1901 (Annelida: Scalibregmatidae) from Brazil. European Journal of Taxonomy 947: 88-108, DOI: 10.5852/ejt.2024.947.2621, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2621/12029
