Global diversity and phylogeny of pelagic shrimps of the former genera <i>Sergestes </i>and <i>Sergia </i>(Crustacea, Dendrobranchiata, Sergestidae), with definition of eight new genera

We revise the global diversity of the former genera Sergia and Sergestes which include 71 valid species. The revision is based on examination of more than 37,000 specimens from collections in the Natural History Museum of Denmark and the Museum of Natural History, Paris. We used 72 morphological characters (61 binary, 11 multistate) and Sicyonella antennata as an outgroup for cladistic analysis. There is no support for the genera Sergia and Sergestes as they have been defined until now. We define and diagnose eight genera of the former genus Sergia (Sergia and new genera Gardinerosergia, Phorcosergia, Prehensilosergia, Robustosergia, Scintillosergia, Challengerosergia, and Lucensosergia) and seven genera of the former genus Sergestes (Sergestes, Deosergestes, Eusergestes, Allosergestes, Parasergestes, Neosergestes, and a new genus Cornutosergestes). An identification key is presented for all genera of the family Sergestidae. The phylogeny of Sergestidae is mainly based on three categories of characters related to: (1) general decapod morphology, (2) male copulatory organs, and (3) photophores. Only simultaneous use of all three character types resulted in a resolved tree with minimal Bootstrap support 75 for each clade. Most genera are interzonal mesopelagic migrants, some are benthopelagic (Scintillosergia, Lucensosergia), bathypelagic (Sergia), or epipelagic (Cornutosergestes). Within each of meso- and benthopelagic genera there is one species with panoceanic distribution, while most species ranges are restricted to a single ocean. The genera demonstrate two different strategies expressed both in morphology and behavior: protective (Eusergestes, Sergestes, Cornutosergestes, Prehensilosergia, Scintillosergia, Lucensosergia, Challengerosergia, Gardinerosergia, Robustosergia, Phorcosergia, Sergia) and offensive (Neosergestes, Parasergestes, Allosergestes, Deosergestes)

Figure 8 in Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda, Sergestidae), with biological remarks

Figure 8. Distribution of Petalidium foliaceum south of Australia (sensu Wasmer, 1993). PF, Polar Front; STF, Subtropical Front.Published as part of &lt;i&gt;Vereshchaka, Alexander L. &amp; Lunina, Anastasia A., 2015, Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda, Sergestidae), with biological remarks, pp. 459-472 in Zoological Journal of the Linnean Society 174 (3)&lt;/i&gt; on page 469, DOI: 10.1111/zoj.12243, &lt;a href="http://zenodo.org/record/10106760"&gt;http://zenodo.org/record/10106760&lt;/a&gt

Figure 6 in Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda, Sergestidae), with biological remarks

Figure 6. The strict consensus trees, principal clades and their bootstrap support (numbers above the clade) and Bremer support (numbers below the clade in circles). A, analysis 1 with Lucifer typus as the outgroup. B, analysis 2 with Aristeomorpha foliacea as the outgroup.Published as part of &lt;i&gt;Vereshchaka, Alexander L. &amp; Lunina, Anastasia A., 2015, Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda, Sergestidae), with biological remarks, pp. 459-472 in Zoological Journal of the Linnean Society 174 (3)&lt;/i&gt; on page 465, DOI: 10.1111/zoj.12243, &lt;a href="http://zenodo.org/record/10106760"&gt;http://zenodo.org/record/10106760&lt;/a&gt

Opaepele

Key to species of the genus &lt;i&gt;Opaepele&lt;/i&gt; &lt;p&gt; 1. Rostrum unarmed dorsally &lt;i&gt;............................................................................................................... Opaepele susannae&lt;/i&gt;&lt;/p&gt; &lt;p&gt;&ndash; Rostrum armed with dorsal teeth or dorsally notched.................................................................................................. 2&lt;/p&gt; &lt;p&gt; 2. Rostrum armed with acute teeth. Ischia and meri of pereopods II&ndash;V unarmed &lt;i&gt;..................................... Opaepele loihi&lt;/i&gt;&lt;/p&gt; &lt;p&gt; &ndash; Rostrum dorsally notched. Posterior margin of telson concave /straight. Ischia of pereopods III&ndash;IV and merus of pereopod III armed with spines &lt;i&gt;............................................................................................. Opaepele vavilovi&lt;/i&gt; sp. nov.&lt;/p&gt;Published as part of &lt;i&gt;Lunina, Anastasia A. &amp; Vereshchaka, Alexander L., 2010, A new vent shrimp (Crustacea: Decapoda: Alvinocarididae) from the Mid-Atlantic Ridge *, pp. 69-74 in Zootaxa 2372&lt;/i&gt; on page 74, DOI: &lt;a href="http://zenodo.org/record/193728"&gt;10.5281/zenodo.193728&lt;/a&gt

Opaepele vavilovi Lunina & Vereshchaka, 2010, sp. nov.

&lt;i&gt;Opaepele vavilovi&lt;/i&gt; sp. nov. &lt;p&gt;(Figs. 1 A&ndash;D, 2A&ndash;H)&lt;/p&gt; &lt;p&gt; &lt;b&gt;Material examined.&lt;/b&gt; Holotype female, cl 8.1 mm, Mid-Atlantic Ridge, Broken Spur vent site, Station 4797, 25.VIII.2005 (Zoological Museum, Moscow State University, Ma 3338). Paratypes: 4 females: cl 10.9, 7.7, 6.0, 4.5 mm; 1 male: cl 6.2 mm, all from Mid-Atlantic Ridge, Broken Spur vent site, Station 4797, 25.VIII. 2005 (Zoological Museum, Moscow State University, Ma 3339). The following paratypes will be deposited in the Oxford Zoological Museum: cl 7.7 mm and 10.9 mm.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Description.&lt;/b&gt; Carapace setose in anterior two-thirds of ventral margin; rostrum subtriangular in crosssection, subacute, dorsally convex, ventrally slightly concave, bearing six inconspicuous notches (Fig. 1 A), reaching as far as mid-length of first segment of antennular peduncle; blunt dorsal carina conspicuous along anterior rostral margin; antennal tooth reaching 0.67 of rostrum length and overreaching cornea, with mediodorsally directed tip (Figs. 1 B&ndash;C).&lt;/p&gt; &lt;p&gt;Pleura of first to third abdominal somites broadly rounded; fourth somite with posterolateral angle produced (Fig. 1 D); fifth somite with posterolateral tooth. Sixth somite 1.5 as long as high.&lt;/p&gt; &lt;p&gt;Telson (Fig. 1 E) elongate, almost orthogonal, 2.6 times as long as wide in its widest proximal margin, distal margin slightly narrower; dorsal margin armed with six pairs of spines of nearly equal size, three anteriormost pairs more medially placed; posterior margin slightly concave, armed with six pairs of spines.&lt;/p&gt; &lt;p&gt;Antennal scale nearly twice as long as wide, distolateral spine somewhat blunt, reaching 0.25 length of blade; anterior margin of scaphocerite broadly rounded. Antennal peduncle reaching to 2/3 length of scaphocerite, basal segment with ventral distal and median teeth.&lt;/p&gt; &lt;p&gt;Mandible with broad incisor, bearing 2 short and 3 long terminal teeth; palp with distal segment bearing plumose setae distally, longest positioned at middle of segment and exceeding it by 1.1 times its length. First maxilla distal endite covered with long, plumose setae along 0.2 of proximal margin and 0.75 of distolateral margin; palp bearing very long plumose mediodistal setae, reaching tip of endite. Second maxilla with narrow palp reaching end of distal endite; scaphognathite with rounded anterior lobe, as wide as long, and narrow triangular posterior lobe covered with shorter setae in its proximal part and very long terminal setae equal in length to entire scaphognathite. Endopod of first maxilliped shorter than palp, bearing two rows of setae on its dorsal and ventral sides; palp abruptly narrowing at about distal &jsercy;oint; epipod with distinct proximal heel, about three times as long as wide in its proximal side. Second maxilliped (Fig. 2 A) covered with plumose setae; distal segment separated from penultimate by oblique suture and bearing dense group of strong setae along 0.80 of its distomedial side. Third maxilliped (Fig. 2 B) slightly longer than antennal scale, ischiomerus bearing long stout spine at articulation with carpus, propodus with a row of strong setae along 0.80 of distoventral side, dorsal margin covered with dispersed, slender setae.&lt;/p&gt; &lt;p&gt;First pereopod (Fig. 2 C) with ischium and merus separated by oblique junction and covered with scattered setae along ventral side; carpus curved at 0.3 of its proximal side; movable finger directed inward; propodus flattened, bearing setae along cutting edge; width of fixed finger in lateral view 3.4 times that of dactylus; ischium 0.4 times, merus 1.4 times, propodus and dactylus 1.4 times as long as carpus, respectively. Second pereopod (Fig. 2 D) covered with long setae; ischium and merus separated by oblique junction; chela with fingers subequal in size and armed with rows of spines directed distally; ischium 0.8 times, merus 1.6 times, propodus 1.1 times, and dactylus 0.7 times as long as carpus, respectively. Third pereopod (Figs. 1 E&ndash;F) with ischium and merus separated by a distinct transverse junction and covered with a few, short setae on medial margins; carpus 1.5 times as short as merus, with a distolateral process; propodus with 17 proximal spines; dactylus 1/14 length of propodus, with one apical and four subterminal ungui. Fourth pereopod (Fig. 2 G) similar in size and form to third pereopod; carpus 1.8 times as short as merus, with a distolateral process; propodus with several, proximal spines; dactylus with one apical and 3 subterminal ungui. Fifth pereopods unknown, broken off in all specimens, probably similar to third and fourth pereopods.&lt;/p&gt; &lt;p&gt;Second to fourth pleopods, each with appendix interna, reaching to about 0.25 of endopod length and hidden amongst stouter, much longer setae in both sexes. Appendix masculina almost as long as appendix interna, bearing eight strong apical setae.&lt;/p&gt; &lt;p&gt;Uropodal exopod somewhat longer than endopod, with distinct diaeresis, movable spine five times as long as fixed distolateral tooth.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Etymology.&lt;/b&gt; The new species is named after the Russian oceanographic research vessel &ldquo;Akademik Sergej Vavilov&rdquo;.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Colour.&lt;/b&gt; Pinkish (based on freshly dead specimens brought to the surface).&lt;/p&gt; &lt;p&gt; &lt;b&gt;Variations.&lt;/b&gt; In the paratypes, the rostrum bears from five to eight small dorsal notches; whilst the posterior margin of the telson harbours 10&ndash;12 spines.&lt;/p&gt; &lt;p&gt; &lt;b&gt;Remarks.&lt;/b&gt; &lt;i&gt;Opaepele vavilovi&lt;/i&gt; sp. nov. differs from the other two species in the genus by having (1) a rostrum armed with small dorsal notches (vs. small teeth in &lt;i&gt;O. loihi&lt;/i&gt; and smooth in &lt;i&gt;O. susannae&lt;/i&gt;), (2) a concave or straight posterior margin of telson (vs. convex in &lt;i&gt;O. loihi&lt;/i&gt; and &lt;i&gt;O. susannae&lt;/i&gt;), and (3) the ischia and merii of the second through to fourth pereiopods armed with several spines (vs. unarmed in &lt;i&gt;O. loihi&lt;/i&gt; and &lt;i&gt;O. susannae&lt;/i&gt;). Further, minor differences between the three species of &lt;i&gt;Opaepele&lt;/i&gt; are detailed in Table 1.&lt;/p&gt; &lt;p&gt; &lt;b&gt;TABLE 1.&lt;/b&gt; Morphological differences between the species of the genus &lt;i&gt;Opaepele&lt;/i&gt;.&lt;/p&gt; &lt;p&gt; Characters &lt;i&gt;Opaepele loihi Opaepele susannae Opaepele vavilovi&lt;/i&gt; sp. nov.&lt;/p&gt;Published as part of &lt;i&gt;Lunina, Anastasia A. &amp; Vereshchaka, Alexander L., 2010, A new vent shrimp (Crustacea: Decapoda: Alvinocarididae) from the Mid-Atlantic Ridge *, pp. 69-74 in Zootaxa 2372&lt;/i&gt; on pages 70-73, DOI: &lt;a href="http://zenodo.org/record/193728"&gt;10.5281/zenodo.193728&lt;/a&gt

Figure 1. A in Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda, Sergestidae), with biological remarks

Figure 1. A, Petalidium obesum, male, ZMUC-CRU-20547. B, Petalidium suspiriosum, YPM IZ 068756, female, syntype. C, P. obesum, male clasping organ. D, Petalidium foliaceum, petasma. E, P. obesum, petasma. LI, lobus inermis; LT, lobus terminalis; PV, processus ventralis; LC, lobus connectens; Lac, lobus accessorius; LA, lobus armatus; PU, processus uncifer.Published as part of &lt;i&gt;Vereshchaka, Alexander L. &amp; Lunina, Anastasia A., 2015, Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda, Sergestidae), with biological remarks, pp. 459-472 in Zoological Journal of the Linnean Society 174 (3)&lt;/i&gt; on page 461, DOI: 10.1111/zoj.12243, &lt;a href="http://zenodo.org/record/10106760"&gt;http://zenodo.org/record/10106760&lt;/a&gt

Distribution of hydrothermal Alvinocaridid shrimps: effect of geomorphology and specialization to extreme biotopes.

The aim of this study is to review of our knowledge about distribution of recently known species of vent shrimps and to analyze factors influencing distribution patterns. Analyses are based upon (1) original material taken during eight cruises in the Atlantic Ocean (a total of 5861 individuals) and (2) available literature data from the Atlantic, Pacific, and Indian Oceans. Vent shrimps have two patterns of the species ranges: local (single vent site) and regional (three--six vent sites). Pacific species ranges are mainly of the local type and the Atlantic species ranges are of the regional type. The regional type of species ranges may be associated with channels providing easy larval dispersal (rift valleys, trenches), while the local type is characteristic for other areas. Specialization of a shrimp genus to extreme vent habitats leads to two effects: (1) an increase in the number of vent fields inhabited by the genus and (2) a decrease of species number within the genus

Acetes H. MILNE EDWARDS 1830

&lt;i&gt;ACETES&lt;/i&gt; H. MILNE EDWARDS, 1830 &lt;p&gt; &lt;i&gt;Diagnosis:&lt;/i&gt; Carapace and abdomen smooth, firm; labrum not much separated from antennae and eyes; rostrum acute, with oblique frontal margin; supraorbital and hepatic teeth present; sixth abdominal somite and telson in males without ventral processes; telson without lateral spines; eyestalks not elongated, cornea well pigmented; third antennular segment without ventral processes, longer than first segment; stylocerite present, mobile; mandible with palp; maxillula in adults with a single endite; first maxilliped with endopod and epipod; second maxilliped with epipod; third maxilliped &lt;i&gt;&lt;&lt;/i&gt; two times as long as first pereopod, not dimorphic sexually, dactyl subdivided; first pereopod with ischium lacking strong movable spines and reduced chela, fingers subequal; second pereopod with merus lacking proximal protrusion and much reduced chela lacking elongated setae, fingers subequal; third pereopod with much reduced chela lacking strong curved spines and elongated setae, fingers subequal; fourth pereopod in female absent or five-segmented, in male absent or threesegmented; fifth pereopod absent or three-segmented in female, absent or one-segmented (only coxa present) in male; uropodal exopod setose for distal outer margin, with small tooth by far not reaching distal end of exopod. Male clasping organ: well developed, with two devel- oped or rudimentary clasping tubercles, no sensory bristles adjacent to clasping tubercle. Petasma: pars astringens absent or present, pars media if present armed with strong claws; pars externa developed. Photophores: dermal organs and organ of Pesta absent. Branchiae: podobranch on somite VIII, anterior arthrobranchs on somites VIII&ndash;XIII, posterior arthrobranchs absent.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type species:&lt;/i&gt; By original designation, &lt;i&gt;Acetes indicus&lt;/i&gt; H. Milne Edwards, 1830.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Species:&lt;/i&gt; &lt;i&gt;Acetes americanus&lt;/i&gt; Ortmann, 1893, &lt;i&gt;Acetes binghami&lt;/i&gt; Burkenroad, 1934, &lt;i&gt;Acetes chinensis&lt;/i&gt; Hansen, 1919, &lt;i&gt;Acetes erythraeus&lt;/i&gt; Nobili, 1905, &lt;i&gt;Acetes indicus&lt;/i&gt; H. Milne Edwards, 1830, &lt;i&gt;Acetes intermedius&lt;/i&gt; Omori, 1975, &lt;i&gt;Acetes japonicus&lt;/i&gt; Kishinouye, 1905, &lt;i&gt;Acetes johni&lt;/i&gt; Nataraj, 1949, &lt;i&gt;Acetes marinus&lt;/i&gt; Omori, 1975, &lt;i&gt;Acetes natalensis&lt;/i&gt; Barnard, 1955, &lt;i&gt;Acetes paraguayensis&lt;/i&gt; Hansen, 1919, &lt;i&gt;Acetes petrunkevitchi&lt;/i&gt; (Burkenroad, 1945), &lt;i&gt;Acetes serrulatus&lt;/i&gt; (Kr&oslash;yer, 1859), &lt;i&gt;Acetes sibogae&lt;/i&gt; Hansen, 1919, &lt;i&gt;Acetes vulgaris&lt;/i&gt; Hansen, 1919.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Remarks:&lt;/i&gt; The genus &lt;i&gt;Acetes&lt;/i&gt; was established by H. Milne Edwards (1830) who described a new species, &lt;i&gt;A. indicus&lt;/i&gt;, from the Ganges estuary. A comprehensive study by Omori (1975) of all valid species of &lt;i&gt;Acetes&lt;/i&gt; included diagnoses and figures of all known species of the genus. This paper disentangled most of the taxonomic questions within the genus and even made it possible to identify all females, which is unique for Sergestoidea as usually only the adult males can be identified with certainty. Our SEM data on the ultrastructure of the petasma have provided hitherto-unknown morphological details and formed a basis for establishing homologies to other taxa, which is a necessity for phylogenetic studies. In the earliest available identification keys to species of &lt;i&gt;Acetes&lt;/i&gt;, males and females were treated separately (e.g. Hansen, 1919), a tradition continued by Omori (1975). Below we provide a combined key for both males and females with citations for the illustrations necessary for reliable identification.&lt;/p&gt;Published as part of &lt;i&gt;Vereshchaka, Alexander L., Lunina, Anastasia A. &amp; Olesen, Jørgen, 2016, Phylogeny and classification of the shrimp genera Acetes, Peisos, and Sicyonella (Sergestidae: Crustacea: Decapoda), pp. 353-377 in Zoological Journal of the Linnean Society 177 (2)&lt;/i&gt; on pages 358-360, DOI: 10.1111/zoj.12371, &lt;a href="http://zenodo.org/record/5364660"&gt;http://zenodo.org/record/5364660&lt;/a&gt