<i>Xibalbanus cozumelensis</i>, a new species of Remipedia (Crustacea) from Cozumel, Mexico, and a molecular phylogeny of <i>Xibalbanus </i>on the Yucatán Peninsula

A new species belonging to the crustacean class Remipedia is described from an anchialine cave system on the island of Cozumel (Mexico), and is illustrated and compared morphologically and molecularly (CO1 and 16S) with closely related taxa. Xibalbanus cozumelensis sp. nov., the first remipede described from Cozumel, is morphologically similar to Xibalbanus tulumensis (Yager, 1987) from the Yucatán Peninsula, but the two species are genetically separate from each other (about 10% in CO1). A phylogenetic (Bayesian) analysis of Yucatán remipede populations based on CO1 and 16S placed them in a monophyletic Xibalbanus (in Xibalbanidae fam. nov.), with X. cozumelensis as most closely related to X. tulumensis. The Yucatán Peninsula and Cozumel have been separate since approx. early Cenozoic (~65 Ma), which suggests allopatric speciation for X. cozumelensis sp. nov. and X. tulumensis. However, the comparatively low genetic divergence between the two species may indicate that there has been gene flow between ‘mainland’ Yucatán and Cozumel long after the geological separation of the two landmasses, e.g., in cave systems under the sea bed, either continuously or sporadically, for example during the Last Glacial Maximum when the sea level was about 120 m lower than today

Monsters in the dark: Systematics and biogeography of the stygobitic genus godzillius (crustacea: Remipedia) from the lucayan archipelago

Remipedia is a stygobitic group commonly associated with coastal anchialine caves. This class consists of 12 genera, ten of which are found within the Lucayan Archipelago. Herein, we describe a new species within the genus Godzillius from Conch Sound Blue Hole, North Andros Island, Bahamas. Godzillius louriei sp. nov. is the third known remipede observed from a subseafloor marine cave, and the first from the Godzilliidae. Remipedes dwell within notoriously difficult to access cave habitats and thus integrative and comprehensive systematic studies at family or genus level are often absent in the literature. In this study, all species of Godzillius are compared using morphological and molecular approaches. Specifically, the feeding appendages of G. louriei sp. nov., G. fuchsi Gonzalez, Singpiel & Schlagner, 2013 and G. robustus Schram, Yager & Emerson, 1986 were examined using scanning electron microscopy (SEM). Species of Godzillius are identified based on the spines of maxilla 1 segment 4 and by the denticles on the lacinia mobilis of the left mandible. A molecular phylogeny using the mitochondrial 16S rRNA and nuclear histone 3 genes recovered G. louriei sp. nov. within the Godzillius clade and 16S genetic distances revealed a 13–15% difference between species of Godzillius

Adding pieces to the puzzle: insights into diversity and distribution patterns of Cumacea (Crustacea: Peracarida) from the deep North Atlantic to the Arctic Ocean

The Nordic Seas have one of the highest water-mass diversities in the world, yet large knowledge gaps exist in biodiversity structure and biogeographical distribution patterns of the deep macrobenthic fauna. This study focuses on the marine bottom-dwelling peracarid crustacean taxon Cumacea from northern waters, using a combined approach of morphological and molecular techniques to present one of the first insights into genetic variability of this taxon. In total, 947 specimens were assigned to 77 morphologically differing species, representing all seven known families from the North Atlantic. A total of 131 specimens were studied genetically (16S rRNA) and divided into 53 putative species by species delimitation methods (GMYC and ABGD). In most cases, morphological and molecular-genetic delimitation was fully congruent, highlighting the overall success and high quality of both approaches. Differences were due to eight instances resulting in either ecologically driven morphological diversification of species or morphologically cryptic species, uncovering hidden diversity. An interspecific genetic distance of at least 8% was observed with a clear barcoding gap for molecular delimitation of cumacean species. Combining these findings with data from public databases and specimens collected during different international expeditions revealed a change in the composition of taxa from a Northern Atlantic-boreal to an Arctic community. The Greenland-Iceland-Scotland-Ridge (GIS-Ridge) acts as a geographical barrier and/or predominate water masses correspond well with cumacean taxa dominance. A closer investigation on species level revealed occurrences across multiple ecoregions or patchy distributions within defined ecoregions.publishedVersio

The Magnitude of Global Marine Species Diversity

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. Results: There are ∼226,000 eukaryotic marine species described. More species were described in the past decade (∼20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are ∼170,000 synonyms, that 58,000–72,000 species are collected but not yet described, and that 482,000–741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7–1.0 million marine species. Past rates of description of new species indicate there may be 0.5 ± 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. Conclusions: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century

Pseudomma islandicum Meland & Brattegard, 2007, n.sp.

Pseudomma islandicum n.sp. Material examined Type material. Holotype (adult male, 11 mm), IMNH- 2191, stn BIOICE 2860. Allotype (adult female, 11 mm), IMNH- 2192, stn BIOICE 2860. Paratypes. Stn BIOICE 2856, 1 adult female (11 mm), IMNH- 2193. Stn BIOICE 2859, 1 immature male (9 mm), 1 immature male (thorax), 2 adult females (11 mm), 1 immature female (10 mm), 1 juvenile (7 mm), IMNH- 2194. Stn BIOICE 2860, 1 immature male, (8), 1 immature male (11 mm), 1 adult female (11 mm), 2 immature females (8 mm), 1 adult female (thorax), 1 immature female (thorax), 3 juveniles, IMNH- 2195. Stn BIOICE 2863, 1 immature male (9 mm), 1 adult female (11 mm). Description Carapace (Fig. 5 A) with anterior margin evenly rounded and anteriorly produced lateral corners. Ocular plate (Fig. 5 A) extending to mid-portion of first segment of antennular peduncle; plate deeply cleft, anterior median portion of plate slightly produced in males; antero-lateral margins coarsely serrated with 20-25 stout setae. Antennal scale (Fig. 5 B) 3.5 times longer than broad; distal terminal denticle on outer margin consisting of one spine; apex extends beyond terminal denticle, without suture, outer margin of apex armed with five setae. Left mandible setal row consisting of three hirsute spines and right mandible setal row consisting of nine or ten entire spines. Distal segment of mandible palp (Fig. 5 C) with three enlarged proximal ventral setae in male and five in female, medial margin with row of nine to 11 setae, dorsal margin with eight setae. Maxillule (Fig. 5 D), apex of coxal lobe armed with three strong setae bordered by three smaller setae placed distal-posterior, distal-ventral, and distal-anterior; anterior lateral margin armed with two setae in medial region; ventral surface and posterior lateral margin supporting seven to nine setae; ventral surface of maxillule basis supporting three setae, posterior lateral margin set with small setae, apex supporting 14 strong cuspidate setae. Maxilla (Fig. 5 E) with three setae on proximal inner margin of endopod; exopod supporting 19–20 lateral setae; coxa with seven or eight setae on dorsal surface, coxal surface set with small denticles, lateral margin of coxa armed with two rows of setae, dorsal row consisting of one large and five smaller setae. First and second thoracic appendages formed as maxillipeds; first maxilliped dactylus fringed with five large setulate setae on each lateral margin; second maxilliped with long nail, dactylus fringed with seven to nine large setulate setae on each lateral margin. Third to eighth thoracic appendages take on the form of long and slender pereopods. Female marsupium consists of three pairs of oostegites arising from the sixth to eighth pereopods, increasing in size posteriorly. Male genital organ extending beyond seventh pereopod, bearing one apical seta. Sixth abdominal somite two times longer than fifth. Pleopods of male biramous; first pleopod with unsegmented endopod and 8 –segmented exopod; second pleopod 8 -segmented endopod and exopod; third to fifth exopods 7 -segmented; third, fourth, and fifth endopods 6 -, 7 -, and 5 -segmented, respectively. The third pleopods three penultimate segments of endopod and exopod support enlarged setae (Fig 6 A); fourth pleopods bear enlarged setae on the three penultimate segments of endopods and four enlarged setae on the four penultimate segments of exopods (Fig. 6 B). Female pleopods uniramous, taking on the form of unsegmented plates and set with apical and ventral surface setae. Uropod endopod (Fig. 6 C) with one ventrally placed strong spinose seta on inner margin near statocyst, outer margin of endopod armed with 13 large setae, and 13 small setae. Telson (Fig. 6 D), distal end of lateral margins armed with six to 11 spinose setae, apex armed with six pairs of spinose setae; apex with one pair of median plumose setae. Etymology The species is named for its present distribution. Distribution Pseudomma islandicum is found at more than 2500 m depths in the eastern Iceland Basin. Remarks Pseudomma islandicum bears close resemblance to P. j a s i Meland & Brattegard, 1995, and a close relationship between these two species is suggested. The erection of a new species is justified based on the telson in P. islandicum being armed with spinose setae on the distal third portion of the lateral margins, whereas in P. jasi the lateral setae do not extend much further than the apex. Also, when compared to P. j a s i, the serrated antero-lateral margins of the ocular plates are quite conspicuous in P. islandicum, opposed to the minute serration seen in P. j a s i. It is interesting to note characters of the mandible palp, where as in P. maasakii n. sp. there are up to five enlarged proximal setae on the distal segment of the palp, which is a character state most often found in Pseudomma species from the Antarctic such as P. a r m a t u m Hansen, 1913, P. belgicae Holt & Tattersall, 1906, and P. antarcticum Zimmer, 1914. Regarding Pseudomma species from the Antarctic a clarification with reference to figured Pseudomma species in Petryashov (2006) is necessary. Note that Petryashov depicts the antennal scales of P. a r m a t u m, P. calmani, and P. belgicae with what resembles apical sutures. As such a suture has never been observed in Pseudomma, it is important to note that the supposed scale sutures, in the three Antarctic species housed in the Russian Academy collections, are actually artifacts of folding during slide preperations (Petryashov, pers. comm).Published as part of Meland, Kenneth & Brattegard, Torleiv, 2007, New Mysida (Crustacea) in the genera Amblyops and Pseudomma from the Iceland Basin, pp. 43-58 in Zootaxa 1628 on pages 51-54, DOI: 10.5281/zenodo.17932

Amblyops trisetosa Nouvel and Lagardere 1976

Amblyops trisetosa Nouvel and Lagardère, 1976 Amblyops trisetosa Nouvel and Lagardère 1976: 1270 –1275. Material examined Type material. Holotype (adult male, 9.0 mm), MNHN-My 45. Paratype (adult male, 9.8 mm), stn Gch 74 (Nouvel and Lagardère, 1976). Additional material. Stn BIOICE 2860, 1 adult female (13 mm), IMNH- 2180. Description Amblyops trisetosa was established by Nouvel and Lagardère (1976) for the reception of two adult males from 740 m in the Bay of Biscay. As this is the first record of a female a full description of this specimen is presented. We have also included holotype descriptions of the male genital organ and features of the male pleopods to accommodate Nouvel and Lagardère (1976). Carapace (Fig. 1 A) with anterior margin evenly rounded, without rostrum, lateral margin straight, posterior dorsal margin exposing last two thoracic somites. Ocular plates (Fig. 1 A) separated, each plate with a well developed and pigmented papilla on medial anterior margins, plate is densely set with minute spinules on anterior and anterolateral margins. Antennal scale three times longer than broad, distal terminal denticle on outer margin consisting of two spines, apex small, not extending beyond terminal denticle, small suture present. Left mandible setal row consisting of eight hirsute spines and right mandible setal row consisting of eight entire spines. Distal segment of mandible palp with one enlarged proximal ventral seta, medial margin with row of eight setae, dorsal margin with seven setae. Maxillule, apex of coxal lobe armed with three strong setae bordered by three smaller setae placed distalposterior, distal-ventral, and distal-anterior; anterior lateral margin armed with two setae in medial region; ventral surface and posterior lateral margin supporting five setae; ventral surface of maxillule basis supporting three setae, posterior lateral margin with small setae, apex supporting 14 cuspidate setae. Maxilla with three setae on proximal inner margin of endopod; exopod supporting 28 lateral setae; coxa with one seta on dorsal surface, coxal surface without spines or denticles, lateral margin of coxa armed with two rows of setae, dorsal row consisting of one large and six smaller setae, setae in ventral row armed with proximal and medial placed denticles. First and second thoracic appendages formed as maxillipeds; first maxilliped with large nail, dactylus fringed with four large setulate setae on each lateral margin; second maxilliped with long nail (0.5 of dactylus length), dactylus fringed with four to five large setulate setae on each lateral margin. Third to eighth thoracic appendages take on the form of long and slender pereopods. Female marsupium consists of three pairs of oostegites arising from the sixth to eighth pereopods, increasing in size posteriorly. Male genital organ short (Fig 1 B), barely extending beyond eighth pereopod, bearing four apical setae. Sixth abdominal somite 1.5 times longer than fifth. Male pleopods biramous; first pleopod with unsegmented endopod and 13 -segmented exopod; second to fourth pleopods with 12 -segmented endo- and 13 -segmented exopods; fifth pleopod with 11 -segmented endo- and 12 -segmented exopod; distal five segments of fourth pleopod endopod bear modified setae, the terminal segment of the fourth pleopod exopod armed with three setae. Female pleopods uniramous, taking on the form of unsegmented plates and set with apical and ventral surface setae. Uropod endopod with four ventrally placed strong spinose setae on inner margin near statocyst in female (Fig. 1 C) and one or two spinose setae in the male, outer margin of endopod armed with 13 large setae, and 13 small setae. Telson (Fig. 1 D) with a broadly rounded and slightly truncate apex, lateral margins armed with 20 spinose setae on each side, apex armed with five pairs of spinose setae and one pair of small medial spinose setae, pair of median plumose setae slightly displaced dorsally on the apex. Remarks When we first started analysing this specimen we suspected it to be a new species that was closely related to Amblyops trisetosa Nouvel and Lagardère, 1976, A. durbani Tattersall, 1955, and to a lesser extent, A. longisquamosus Murano and Mauchline, 1999. After a closer inspection of type specimens of the said species, we realized that the close similarity with A. trisetosa coupled with the fact that we had only one female specimen would not allow for the erection of a new Amblyops. However, by including this Iceland Basin female we have introduced some intraspecific variation in A. trisetosa that must be emphasized. The mandible palp of the female has eight medial and seven dorsal setae opposed to seven medial and five dorsal setae in A. trisetosa males. The maxilla endopod in the female is set with 28 lateral setae, but no more than 17 in the males. There are slight differences in the shape and armature of the telson. The apex of the female telson is more rounded and supports four pairs of spines while male apex is more truncated and supports three pairs of spines. Also, the proximal inner margin of the female uropodal endopod is set with four strong setae; in the male there are one or two. With the new definition of A. trisetosa, similarity and suspected relationship with A. durbani becomes quite conspicuous. The only characters separating these two species are the lateral armature of the telson and slight differences in ocular plate morphology. Considering the geographical range of these two species, South Africa, Bay of Biscay, and now the Iceland Basin, future studies on phylogenetic history of hyperbenthic mysids including Amblyops species from these regions would undoubtedly contribute towards our understanding of deep-sea biogeographics.Published as part of Meland, Kenneth & Brattegard, Torleiv, 2007, New Mysida (Crustacea) in the genera Amblyops and Pseudomma from the Iceland Basin, pp. 43-58 in Zootaxa 1628 on pages 44-46, DOI: 10.5281/zenodo.17932

Pseudomma maasakii Meland & Brattegard, 2007, n. sp.

Pseudomma maasakii n. sp. Pseudomma sp. Murano and Mauchline 1999: 279 –280. Pseudomma sp. M&M Meland 2004: 3; Meland and Willassen 2004: 18 S rRNA (AY 624301), COI mtDNA (AY 624281). Material examined Type material. Holotype (adult male, 16 mm), IMNH- 2183, stn BIOICE 2860. Allotype (adult female, 19 mm), ZMBM- 68270, stn BIOICE 3167. Paratypes, Stn BIOICE 2856, 2 females (18 mm), IMNH- 2184. Stn BIOICE 2859, 1 adult male (15 mm), 1 immature female (16 mm), IMNH- 2185. Stn BIOICE 2860, 1 adult female (thorax), 1 juvenile (8 mm) IMNH- 2186. Stn BIOICE 2864, 1 male (14 mm), IMNH- 2187. Stn BIO- ICE 3162, adult female (19 mm), IMNH- 2188. Stn BIOICE 3164, adult female (18 mm), 2 juveniles, IMNH- 2189. Stn BIOICE 3167, 1 adult female (19 mm), IMNH- 2190. Description Carapace (Fig. 3 A) with anterior margin evenly rounded and anteriorly produced lateral corners. Ocular plate (Fig. 3 A, B) extending to mid-portion of first segment of antennular peduncle; plate deeply cleft, medial section slightly produced in males, anterior portion of dorsal surface finely serrated with minute spinules; antero-lateral margins armed with eight minute setae. Antennal scale (Fig. 3 C) three times longer than broad; distal terminal denticle on outer margin consisting of two to three spines; apex extending beyond terminal denticle, without suture, outer margin of apex armed with five setae. Left mandible setal row consisting of three hirsute spines and right mandible setal row consisting of eight entire spines. Distal segment of mandible palp (Fig. 4 A) with five enlarged proximal ventral setae, medial margin with row of eight to 11 setae, dorsal margin with five to six setae. Maxillule (Fig. 4 B), apex of coxal lobe armed with three strong setae bordered by three smaller setae placed distal-posterior, distal-ventral, and distal-anterior; anterior lateral margin armed with four setae in medial region; ventral surface and posterior lateral margin supporting eight to ten setae; ventral surface of maxillule basis supporting three setae, posterior lateral margin armed with robust setae, apex supporting 14 strong cuspidate setae. Maxilla (Fig. 4 C) with three setae on proximal inner margin of endopod; exopod supporting 24-28 lateral setae; coxa with one or two setae on dorsal surface, coxal surface without spines or denticles, lateral margin of coxa armed with two rows of setae, dorsal row consisting of one large and four or five smaller setae. First and second thoracic appendages formed as maxillipeds; first maxilliped with large nail bearing five denticles, dactylus fringed with four to five large setulate setae on each lateral margin; second maxilliped with small nail, dactylus fringed with nine to ten large setulate setae on each lateral margin. Third to eighth thoracic appendages take on the form of long and slender pereopods. Female marsupium consists of three pairs of oostegites arising from the sixth to eighth pereopods, increasing in size posteriorly. Male genital organ extending beyond seventh pereopod, bearing two apical setae. Sixth abdominal somite two times longer than fifth. Pleopods of male biramous; first pleopod with unsegmented endopod and 12 –segmented exopod; second to fourth pleopods with 10 -segmented endo- and exopods; fifth pleopod with 9 -segmented endo- and exopods; distal setae on third and fourth pleopods not modified. Female pleopods uniramous, taking on the form of unsegmented plates and set with apical and ventral surface setae. Uropod endopod (Fig. 4 D) with one ventrally placed strong spinose seta on inner margin near statocyst, outer margin of endopod armed with 13 large setae, and 16 small setae. Telson (Fig. 4 E), lateral margins entire, apex armed with two pairs of spinose setae; apex with one pair of median plumose setae. Etymology The species was first recognized by Murano and Mauchline (1999) and is named in honour of Dr. Maasaki Murano for his huge contribution to mysid taxonomy. Distribution Three specimens of Pseudomma maasakii have earlier been recorded from the Rockall Trough as stomach content in the deep-water grenadier species Nematonurus armatus (Hector, 1875) and Coryphaenoides guentheri (Vailant, 1888) (Murano and Mauchline 1999). The present BIOICE material extends its species range into 2300 m depths of the Iceland Basin. Remarks Due to the shared telson characters with two pairs of apex setose setae and the absence of lateral spinose setae, P. maasakii resembles P. m a t s u i Murano, 1966. However, it is easily distinguishable from all Pseudomma species based on the antennal terminal denticle consisting of two to three spines (Fig. 3 C), and also the anterior lateral margin of the maxillule coxal lobe that is armed with four setae in the medial region (Fig. 4 B).Published as part of Meland, Kenneth & Brattegard, Torleiv, 2007, New Mysida (Crustacea) in the genera Amblyops and Pseudomma from the Iceland Basin, pp. 43-58 in Zootaxa 1628 on pages 48-51, DOI: 10.5281/zenodo.17932

First multigene phylogeny of Cumacea (crustacea: Peracarida)

Cumaceans are small peracarid crustaceans that can be remarkably diverse and important benthic organisms. Despite their ubiquitous presence in soft sediments, no well-resolved phylogeny currently exists, which impedes ecological and evolutionary studies of the group. We present a phylogeny based on Bayesian inference of six markers (18S, 28S, 12S, 16S, CytB and COI), which recovers monophyly of the order, a deep split between telson and pleotelson bearing groups, and monophyly of four of the seven included families, including monophyletic Pseudocumatidae, Lampropidae, Bodotriidae and Nannastacidae. The only species representing the family Gynodiastylidae in our dataset was positioned among members of Diastylidae in the phylogenetic analyses. However, this result is based on a single partial COI sequence; thus, we consider it doubtful, and the family Diastylidae are otherwise recovered as a monophyletic family. The family Leuconidae is split into two well-supported clades, a clade containing Antarctic members of the genus Leucon and a separate clade containing non-Antarctic members of the genera Leucon and Eudorella. The phylogeny is a great stride forwards, as it supports most families as monophyletic, making generic level phylogenies a plausible endeavour in the future.publishedVersio