identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
03DCD266FFE7B119FCF3F98D8C2C677A.text	03DCD266FFE7B119FCF3F98D8C2C677A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon mercedae % Pereira 1986	<div><p>Palaemon mercedae</p><p>This species has a high genetic differentiation in relation to the other species of Palaemon s.s., with uncorrected divergence of 0.1900 (±0.0134) for the 16S gene, 0.2305 (±0.0169) for COI and 0.194 (±0.0176) for H3 (Tables S3–S5). The time of divergence between P. mercedae and Palaemon s.s. was 21.3 Mya (HDP 17.5–25.0 Mya).</p><p>Palaemon sensu stricto</p><p>Among the species of Palaemon s.s., only P. northropi was not recovered as monophyletic, being intercalated by P. floridanus specimens. The time of divergence between the P. northropi + P. floridanus clade and the other species of Palaemon s.s. was estimated at 15.9 Mya (HDP: 13.2–18.9 Mya). Palaemon paivai was recovered as monophyletic, with a genetic divergence of 0.0290 (±0.0073) for 16S, 0.1029 (±0.0115) for COI and 0.0089 (±0.0049) for H 3 in relation to its sister, P. ritteri . In addition, a species with no previous record in Brazil was identified ( Palaemon octaviae), which was recovered as close to P. argentinus . The genetic divergence between P. octaviae and P. argentinus was 0.1021 (±0.0133) for 16S, 0.11130 (±0.0128) for COI and 0.0365 (±0.0103) for H3, with time of divergence estimated at 7.5 Mya (HDP 5.4–9.5 Mya).</p><p>Intraspecific variability in Palaemon s.s. species was lower than that found in the “ Alaocaris ” species (Table S6). All species showed genetic divergence lower than 0.01 for 16S and COI and 0.001 for H3. The clade P. northropi + P. floridanus showed a small structuring, with a divergence of 0.0096 (±0.0020) for COI.</p></div>	https://treatment.plazi.org/id/03DCD266FFE7B119FCF3F98D8C2C677A	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFE2B11AFCF7FAF1890B67A6.text	03DCD266FFE2B11AFCF7FAF1890B67A6.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon argentinus (Nobili 1901)	<div><p>3.2.1 | Palaemon argentinus (Nobili, 1901) —</p><p>Figures 4a, 5e,g and 6a</p><p>Mandibular palp absent. Branchiostegal spine next to branchiostegal suture. Fifth thoracic sternite with median acute projection present in adult males. Appendix masculina slender and slightly curved, up to 1.6 times length of appendix interna; row of setae extends almost to entire length of anterior face of appendix masculina; additional setae on proximal third. Inner pair of stout setae of distal margin of telson about 2.8 times length of outer pair.</p></div>	https://treatment.plazi.org/id/03DCD266FFE2B11AFCF7FAF1890B67A6	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFE2B11BFCF7F9518CC864CF.text	03DCD266FFE2B11BFCF7F9518CC864CF.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon carteri (Gordon 1935)	<div><p>3.2.2 | Palaemon carteri (Gordon, 1935) —</p><p>Figures 4b, 5b,l and 6b</p><p>Ventral margin of rostrum with three–seven teeth, usually four or more. Mandibular palp absent. Branchiostegal spine placed approximately half the distance between antennal spine and branchiostegal suture. Projection of anterolateral margin of first segment of the antennular peduncle not reaching, rarely almost reaching, dorsal distal margin of second segment. Appendix masculina slender, straight, up to 1.3 times length of appendix interna; setae present mainly in apex of appendix masculina.</p></div>	https://treatment.plazi.org/id/03DCD266FFE2B11BFCF7F9518CC864CF	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFE3B11BFFBBF9A68ECD6441.text	03DCD266FFE3B11BFFBBF9A68ECD6441.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon ivonicus (Holthuis 1950)	<div><p>3.2.3 | Palaemon ivonicus (Holthuis, 1950) —</p><p>Figures 4c, 5m and 6c</p><p>Rostrum not overreaching tip of scaphocerite, ventral margin with one–four teeth, usually two or three. Mandibular palp absent. Branchiostegal spine placed approximately half the distance between antennal spine and branchiostegal suture. Projection of anterolateral margin of first segment of the antennular peduncle reaching, usually overreaching, dorsal distal margin of second segment. Appendix masculina slender, straight or slightly curved, up to 1.6 times length of appendix interna; row of setae extending from apex to middle of length of anterior face of appendix masculina.</p></div>	https://treatment.plazi.org/id/03DCD266FFE3B11BFFBBF9A68ECD6441	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFE3B11BFCF3FA308E8F6757.text	03DCD266FFE3B11BFCF3FA308E8F6757.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon mercedae (Pereira 1986)	<div><p>3.2.4 | Palaemon mercedae (Pereira, 1986) —</p><p>Figures 4d, 5i and 6d</p><p>Appendix masculina strong and straight. Telson bearing four–nine pairs of plumose setae and two pairs of stout setae on distal margin.</p></div>	https://treatment.plazi.org/id/03DCD266FFE3B11BFCF3FA308E8F6757	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFE3B11BFCF3F93E8ECC66B2.text	03DCD266FFE3B11BFCF3F93E8ECC66B2.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon northropi (Rankin 1898)	<div><p>3.2.5 | Palaemon northropi (Rankin, 1898) —</p><p>Figures 4e, 5c,j and 6e</p><p>Mandibular palp present. Branchiostegal spine next to branchiostegal suture. Carpus 0.8 to 1.0 length of chela. Appendix masculina slender and slightly curved, up to 1.3 times length of appendix interna; row of setae extending from tip to two‐third length of anterior face of appendix masculina.</p></div>	https://treatment.plazi.org/id/03DCD266FFE3B11BFCF3F93E8ECC66B2	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFECB114FFB0FCF58D8C65C1.text	03DCD266FFECB114FFB0FCF58D8C65C1.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon octaviae (Chace 1972)	<div><p>3.2.6 | Palaemon octaviae (Chace, 1972a) —</p><p>Figures 4f, 5f,h and 6f</p><p>Mandibular palp absent. Branchiostegal spine next to branchiostegal suture. Fifth thoracic sternite without median acute projection in adult males. Appendix masculina slender, straight or slightly curved, up to 1.5 times length of appendix interna; row of setae extending from apex to 2/3 of length of anterior face of appendix masculina; without additional setae on proximal third. Inner pair of stout setae of distal margin of telson about 4.2 times length of outer pair.</p></div>	https://treatment.plazi.org/id/03DCD266FFECB114FFB0FCF58D8C65C1	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFECB114FFB0FAB38F05673F.text	03DCD266FFECB114FFB0FAB38F05673F.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon paivai Fausto Filho 1967	<div><p>3.2.7 | Palaemon paivai Fausto Filho, 1967 —</p><p>Figures 4g, 5k and 6g</p><p>Rostrum with ventral margin strongly arched. Mandibular palp present. Branchiostegal spine next to branchiostegal suture. Carpus 0.4 to 0.6 length of chela. Appendix masculina slender and slightly curved, up to 1.4 times length of appendix interna; row of setae extends from tip to almost entire length of anterior face of appendix masculina.</p></div>	https://treatment.plazi.org/id/03DCD266FFECB114FFB0FAB38F05673F	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFECB114FFB0F9D68C5C669A.text	03DCD266FFECB114FFB0F9D68C5C669A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon pandaliformis (Stimpson 1871)	<div><p>3.2.8 | Palaemon pandaliformis (Stimpson, 1871) —Figures 4h, 5d,o and 6h</p><p>Mandibular palp present. Projection of anterolateral margin of first segment of antennular peduncle reaching dorsal distal margin of second segment. Appendix masculina slender, up to 1.3 times length of appendix interna; row of setae extending from tip to almost half of length of anterior face of appendix masculina.</p></div>	https://treatment.plazi.org/id/03DCD266FFECB114FFB0F9D68C5C669A	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFECB114FCF7FCF5899D65A2.text	03DCD266FFECB114FCF7FCF5899D65A2.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon yuna Carvalho, Magalhaes, & Mantelatto 2014	<div><p>3.2.9 | Palaemon yuna Carvalho, Magalhães &amp; Mantelatto, 2014 —Figures 4i, 5n and 6i</p><p>Rostrum overreaching the scaphocerite; ventral margin with two–five teeth, usually three or four. Mandibular palp absent. Projection of anterolateral margin of first segment of antennular peduncle reaching dorsal distal margin of second segment. Appendix masculina slender, straight, up to 1.3 times length of appendix interna; row of setae extending from apex to middle of length of anterior face of appendix masculina; additional sparse setae on mesiodistal face.</p></div>	https://treatment.plazi.org/id/03DCD266FFECB114FCF7FCF5899D65A2	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFECB115FCF7F96E881061F3.text	03DCD266FFECB115FCF7F96E881061F3.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon mercedae (Pereira 1986)	<div><p>4.1.1 | Palaemon mercedae</p><p>Among the species of the “ Palaemon ” lineage, which present the projection of the anterolateral margin of the first segment of antennular peduncle not reaching the middle of the second segment, P. mercedae can be easily distinguished from the remaining Palaemon s.s. by bearing four–nine pair of plumose setae and two pairs of short stout setae on the distal margin of the telson, with inner pair of stout setae not overreaching the tip of the telson, and three teeth on the incisor of the left mandible.</p><p>Although efforts have been made to obtain sequences of individuals from all locations with morphological samples, the amplification of the regions of interest could be performed only for one sample of P. mercedae obtained during fieldworks. Due to the absence of more sequences of the species, we could not analyse the intraspecific genetic variability. However, the sequence obtained indicates a clear distinction in relation to the other Palaemon species from Brazil. In addition, there is no evidence for the proposition of any species closely related to P. mercedae, since no consistent morphological differences were found within the characters analysed between the Brazilian specimens and those from the type locality (Atabapo River, Chamuxina, Amazonas, Venezuela). Further collecting efforts to obtain specimens suitable for molecular analyses along the species distribution are necessary to evaluate the existence of cryptic species and to re‐evaluate small variations in the external morphology.</p><p>Palaemon mercedae may present a distribution pattern similar to P. ivonicus + P. yuna (Carvalho et al., 2014), since it occurs both in the Amazon basin and in the Orinoco basin. However, the divergence time between P. mercedae and Palaemon s.s. (estimated at approximately 21 My) is older than the estimates of divergence among the other Amazonian species. Although this value has a wide degree of uncertainty, we suggest that this Amazonian species diverged from Palaemon s.s. in an event different from that associated with the other species of this region.</p><p>Furthermore, the pattern of larval development between P. mercedae and the other species of the “ Palaemon ” lineage is significantly different. Whereas the land‐locked P. mercedae exhibits an extremely abbreviated postembryonic development (Magalhães, 1988), the marine or estuarine P. argentinus, P. floridanus, P. northropi and P. paivai have extended larval development (Abrunhosa, Costa, Moura, &amp; Pires,2009; Knowlton &amp; Vargo, 2004; Menu‐Marque, 1973; Moura, Abrunhosa, &amp; Pereira Da Costa,1990, respectively). Although the evolution of larval development patterns in palaemonid shrimps does not reflect phylogenetic traits (Botello &amp; Alvarez, 2013; Magalhães &amp; Walker, 1988; Murphy &amp; Austin, 2005), the high degree of “freshwaterization” shown by P. mercedae may indicate an early invasion of the continental aquatic habitats and consequently divergence from the other species of Palaemon s.s.</p><p>As suggested by Carvalho et al. (2017), P. mercedae should be allocated in a new genus, so far monospecific. The main diagnostic characteristics for the distinction between P. mercedae and the Brazilian species of Palaemon s.s will also be employed in distinguishing the new genus. Thus, although P. mercedae is still treated here as a species of Palaemon, future comparative studies with the species should consider the phylogenetic status outside Palaemon s.s.</p></div>	https://treatment.plazi.org/id/03DCD266FFECB115FCF7F96E881061F3	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
03DCD266FFEDB117FCF3FEA38F796058.text	03DCD266FFEDB117FCF3FEA38F796058.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaemon Weber 1795	<div><p>4.1.2 | Palaemon sensu stricto</p><p>The species of Palaemon s.s. which occur in Brazil ( P. argentinus, P. paivai, P. northropi and P. octaviae) can be separated by the presence or absence of a mandibular palp and the projection on the fifth male thoracic sternite, proportion between carpus and chela and relative size of stout setae on the distal margin of the telson. Rostral characters, appendix masculina and the anterolateral projection of the first segment of antennular peduncle are also useful for distinguishing the Brazilian species of Palaemon s.s.</p><p>Although the external morphology of P. ritteri and P. paivai is very similar and overlaps in the diagnostic characters proposed by Fausto Filho (1967), new characters of the appendix masculina proposed herein allow the distinction between them. Palaemon paivai has a stronger and curved appendix, with a dense row of setae on almost the entire length of the anterior face of the appendix masculina. Palaemon ritteri has a slender and straight appendix masculina, with a sparse row of setae on the entire length of the anterior face of the appendix (Figure S4). The name P. ritteri has been attributed to some populations found in Pará and Ceará (Ferreira et al., 2010; Gomes‐Correa, 1980). However, a population earlier on attributed to P. ritteri from São João de Pirabas (Pará), and included in our molecular analysis, was allocated outside the clade that includes the Pacific population of this species. Although histone H3 is a conserved gene, the sequence obtained from the topotype of P. paivai allowed the confirmation of a close relationship between individuals from Pará and Ceará, which were separated from the populations of the Pacific. In addition, analysing the appendix masculina from specimens used in previous works, we discovered that P. ritteri in Brazil represent a misidentification, being P. paivai in fact. The analysis of the samples from the Atlantic slope of Panama and Venezuela cited by Holthuis (1952) also revealed higher similarity of the appendix masculina with P. paivai . Therefore, we suggest that P. ritteri and P. paivai are sibling species separated after the complete closure of the isthmus of Panama, supporting the use of this lineage as a calibration point for recent phylogenetic divergence in Palaemonidae .</p><p>Palaemon northropi was not recovered as monophyletic. It was intercalated by P. floridanus specimens, which was described by Chace (1942) from western Florida specimens. Some of the characters proposed by Chace (1942) for distinguishing both species were inconsistent in the analysis conducted by Holthuis (1952). Additionally, Knowlton and Vargo (2004) emphasized that the larval morphology of the two species is almost identical. Despite this similarity, Holthuis (1952) maintained P. floridanus as a valid species and reported that P. northropi has three or four teeth on the ventral margin of the rostrum and fingers of the second pereopod up to 2/3 of the length of the palm, while P. floridanus has five to seven teeth and more than 2/3.</p><p>The topology indicates that the distinction between P. northropi and P. floridanus based on the number of dorsal teeth and the relationship between the size of the fingers and the size of the chela may not represent natural groups. Although the morphological distinction between the two species may be easy when P. floridanus individuals from the Gulf of Mexico are compared to P. northropi from other regions, this distinction is not very clear when specimens of P. floridanus from the Caribbean and P. northropi are compared. Baeza and Fuentes (2013) reported the genetic differentiation between P. floridanus from the Gulf of Mexico (west coast of Florida) and those from the east coast of Florida. Additionally, they described high similarity between individuals from eastern Florida and Panama. These results indicate that the populations of the Gulf of Mexico have a distinct phylogeographic history from the remaining populations, being the result of an event of recent divergence (Baeza &amp; Fuentes, 2013), which may be associated with the establishment of a morphological pattern in this area, which was recognized by Chace (1942) as compatible with the species level. A similar phylogeographic pattern for the Gulf of Mexico populations of the freshwater shrimp Atya scabra (Leach, 1816) was discovered by Oliveira, Terossi, and Mantelatto (2019). However, the phylogenetic relationships recovered in the present work indicate that the diagnostic characters of P. floridanus may be autapomorphies that do not represent a lineage other than P. northropi . In this context, an expansion of sampling in the Gulf of Mexico, with the inclusion of individuals with more than five teeth in the ventral margin of the rostrum, is essential for a better understanding of the phylogenetic relationships between P. floridanus and the populations of P. northropi and to test the representativeness of this character on a possible distinct lineage.</p><p>A small genetic structuring was observed, with a tendency of separation, between specimens of the North and South Atlantic. As both the type localities of P. northropi and P. floridanus are in the North Atlantic, taxonomic adjustments may be necessary if the topology is confirmed after the amplification of samples from the Gulf of Mexico, resulting in P. floridanus being placed in the synonymy of P. northropi . The genetic structuring could justify the revalidation of another synonym, Palaemon brachylabis Rathbun, 1902, whose topotypic specimen (Mamanguape River, Paraíba) was included in our analyses and, in general, showed a closer relationship with individuals from the South Atlantic. Nevertheless, low genetic divergence and the absence of morphological characters or other supporting evidence indicate that the genetic structuring found can be attributed to a reduction in gene flow, and this divergence is considered to be at the population level.</p><p>An unrecorded species for Brazil was identified after the molecular comparison of some populations of Rio de Janeiro and Pará in relation to the other Palaemon from Brazil. Although specimens of the type locality of P. octaviae (Chace, 1972a) were not included in the molecular analysis, the absence of distinctive characters between the later species and newly recorded one from Brazil allows us to assign the name P. octaviae to the populations found in Brazil. In addition, the first record of P. octaviae is made herein for Venezuela (data in Appendix S1), thus expanding the distribution of the species previously restricted to Mexico and Guadalupe to South America (Venezuela and Brazil —states of Pará and Rio de Janeiro).</p><p>Palaemon octaviae has high morphological similarity with P. argentinus, as indicated by Chace (1972a). However, the molecular data indicate a clear separation between the two species and differences in the appendix masculina, male thoracic sternite, stout setae of the telson and shape of the rostrum allow the separation between them. Distinguishing P. octaviae from the species of Palaemon s.s. occurring in Brazil can be done by the absence of a mandibular palp in P. octaviae and comparing characters of the rostrum, distal margin of the telson, appendix masculina and the fifth thoracic sternite.</p><p>Both P. octaviae and P. northropi have a wide disjunct distribution, extended larval development (judging by the observed number and size of the eggs), and occur in the same environments. Considering the distribution of P. northropi in both North Atlantic and South Atlantic with low intraspecific genetic divergence, it is suggested that P. octaviae may also show the same geographical amplitude. The species has a markedly disjunct distribution in Brazil, without records from the north‐east region so far. A comparable pattern was also reported for a recently described alpheid species (Almeida, Terossi, &amp; Mantelatto, 2014), which in Brazil occurs in Pará, Bahia and São Paulo, in similar environments to those in which P. octaviae was collected. Sampling efforts at such environments but including other regions of Brazil may reduce distribution gaps, since the absence of structuring on the analysed genes may suggest the existence of recent gene flow in both Alpheus petronioi (Almeida et al., 2014) and P. octaviae, and the existence of intermediate populations along the distribution.</p><p>Alternatively, the current distribution of P. octaviae may represent a relict distribution as a result of interactions with other species of the group. The sympatric distribution of P. octaviae and P. northropi, the ecological similarity between the two species in terms of habitat and some reproductive features, and the larger size of P. northropi do not allow the rejection, a priori, of the hypothesis of competitive exclusion of P. octaviae by P. northropi . This hypothesis is reinforced by the fact that the two species are the result of two distinct colonization events on the American continent (see Carvalho et al., 2017). However, comparative ecological studies with these species are necessary so that the competitive exclusion hypothesis can be tested.</p></div>	https://treatment.plazi.org/id/03DCD266FFEDB117FCF3FEA38F796058	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Carvalho, Fabrício L.;Magalhães, Célio;Mantelatto, Fernando L.	Carvalho, Fabrício L., Magalhães, Célio, Mantelatto, Fernando L. (2019): A molecular and morphological approach on the taxonomic status of the Brazilian species of Palaemon (Decapoda, Palaemonidae). Zoologica Scripta 49 (1): 1-16, DOI: 10.1111/zsc.12394, URL: https://doi.org/10.1111/zsc.12394
