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

Petalidium foliaceum Bate 1881

&lt;i&gt;PETALIDIUM FOLIACEUM&lt;/i&gt; BATE, 1881 (FIGS 2A, 3A&ndash;C) &lt;p&gt; &lt;i&gt;Petalidium foliaceum&lt;/i&gt; Bate, 1881: 194; 1888: 349, plate 60. Hansen, 1896: 936; 1903: 54, plate II, figure I. Illig, 1914: 372, figures 31&ndash;34. Stebbing, 1914: 284, plate 28. Burkenroad, 1937: 326. Hale &amp; Johnston (1941): 261, figures 1, 2.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Material examined:&lt;/i&gt; Dana stations 3630-1 (1 f 11 mm, catalogue number YPM IZ 040426), 3642-2 (2 ff 10.5&ndash; 16.5 mm; 1 juv 6 mm, catalogue number YPM IZ 040430), 3642-3 (2 ff 9&ndash;10 mm, catalogue number YPM IZ 040427), 3642-4 (1 f 6 mm, catalogue number YPM IZ 040428), 3656-1 (1 f 22 mm, catalogue number YPM IZ 040425), 3656-3 (1 f 15 mm, catalogue number YPM IZ 040429), 3978-7 (1 m 8&frac12;mm), 3978-8 (6 juv 5 mm). Challenger Expedition, Station 159, South Australia (syntype, Natural History Museum, catalogue number 1888.22), Station 146, Marion Island (five syntypes, Natural History Museum, catalogue number 1888.22 (four syntypes) and 1903.6.6.16 (1 syntype).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type material:&lt;/i&gt; Six syntypes of &lt;i&gt;Petalidium foliaceum&lt;/i&gt;, Natural History Museum (see above).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type locality:&lt;/i&gt; Off Marion Island, 46&deg;46&prime;S, 45&deg;31&prime;E, depth 2516 m. South of Australia, 47&deg;25&prime;S, 130&deg;22&prime;E, depth 3935 m.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Diagnosis:&lt;/i&gt; Hepatic spine present; petasma with LAc (3&ndash;4 hooks) stronger than LA (1&ndash;2 hooks), LT bearing 4&ndash;5 and 1&ndash;2 hooks on branches; no arthrobranchs on somite XIII.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Remarks:&lt;/i&gt; Both males and females of this species may be distinguished from the other species of the genus by the absence of any arthrobranchs above pereopod IV. In addition, in males, the Lac on the petasma is significantly more robust than the LA. According to our data, any specimens found south of 35&deg;S belong to this species. &lt;i&gt;Petalidium foliaceum&lt;/i&gt; and &lt;i&gt;P. obesum&lt;/i&gt; cooccur in the South Atlantic between 30&deg;S and 35&deg;S; if taken from in this area, &lt;i&gt;P. obesum&lt;/i&gt; is easily distinguished by the absence of an hepatic spine and by its much more slenderer Lac.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Ethymology:&lt;/i&gt; from the Greek &lsquo;foliaceum&rsquo;, meaning foliaceous, leaf-like.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Geographical distribution (Fig. 7):&lt;/i&gt; Most of the southern seas between 35&deg;S and 66&deg;S: South Atlantic, South of Africa (Illig, 1914; Kensley, 1971, 1981; Dana material), southern Indian Ocean, (Bate, 1888; Stebbing, 1914; Hale &amp; Johnston, 1941), south of Australia (Bate, 1888; Iwasaki &amp; Nemoto, 1987), Antarctic Polar Frontal Zone of the Indian Ocean (Pakhomov &amp; Froneman, 2000). The species was recorded south of the Polar Front, in Western Antarctica (Tiefenbacher, 1991), Prydz Bay (69&deg;0&prime; 0&Prime;S, 75&deg;0&prime; 0&Prime;E; Ikeda, 2013), and the Scotia and Weddell Seas (Lancraft, Torres &amp; Hopkins, 1989; Arntz &amp; Gorny, 1991).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Vertical distribution:&lt;/i&gt; Recorded from the Dana stations 1500&ndash;5000-m wire corresponding to approximately 500&ndash;1700 m of actual depth (Vereshchaka, 2000). Hale &amp; Johnston (1941) reported the species from similar depths (1000&ndash;2000 m).&lt;/p&gt; &lt;p&gt; &lt;i&gt;PETALIDIUM OBESUM&lt;/i&gt; (KR&Oslash;YER, 1859)&lt;/p&gt; &lt;p&gt;(FIGS 2B, 4A&ndash;E)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Sergestes obesus&lt;/i&gt; Kr&oslash;yer, 1859: 257, 279, plate 4 (figure 10a&ndash;f)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Sergestes sanguineus&lt;/i&gt; Chun, 1889: 538 (mastigopus stage)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Petalidium obesum&lt;/i&gt; Hansen, 1896: 968; 1903: 56; 1922: 190, plate 11 (figures 3, 4). Burkenroad, 1937: 324. Wasmer, 1974: 165&lt;/p&gt; &lt;p&gt; &lt;i&gt;Petalidium foliaceum&lt;/i&gt; non Bate, Illig, 1927: 282, figures 1&ndash;5&lt;/p&gt; &lt;p&gt; &lt;i&gt;Material examined:&lt;/i&gt; Dana stations 1142-4 (3 mm 6.5&ndash; 7.5 mm; 5 ff 7.5&ndash;10 mm); 1156-5 (1 m 6 mm; 6 ff 7.5&ndash; 9 mm); 1156-7 (4 m 6.5&ndash;7.5 mm; 10 ff 7.5&ndash;9 mm); 1156-9 (1 f 7.5 mm); 3978-7 (1 m 8 mm; 3 ff 8&ndash;10 mm); 3980-7 (6 mm 6.5&ndash;8 mm; 7 ff 8&ndash;10 mm); 3980-8 (3 mm 6&ndash;9 mm; 3 ff 6 mm); 3978-4 (2 mm 6 mm; 1 f 9 mm)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type material&lt;/i&gt;: holotype of &lt;i&gt;Sergestes obesum&lt;/i&gt; (Kr&oslash;yer, 1859), Zoological Museum, Copenhagen University, catalogue number CRU-007582.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type locality:&lt;/i&gt; Central Atlantic, 4.5&deg;N, 21.5&deg;W.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Diagnosis:&lt;/i&gt; Hepatic spine absent in adults; petasma with LAc (1&ndash;3 hooks) more slender than LA (6&ndash;10&lt;/p&gt; &lt;p&gt;hooks), LT bearing 0&ndash;3 and 1&ndash;3 hooks on branches; arthrobranchs on somite XIII lamellar.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Remarks:&lt;/i&gt; Both males and females of this species may be distinguished from the other species of the genus (1) by the absence of an hepatic spine in adults and (2) by the arthrobranchs above pereopod IV being lamellar. In addition, in males, the Lac of the petasma is much more robust than the LA. According to our data, any specimens found in the Atlantic Ocean North of 30&deg;S belong to this species.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Geographical distribution (Fig. 7):&lt;/i&gt; Atlantic Ocean between 45&deg;N and 35&deg;S: of Cape Verde, Canary Islands, Azores Islands (Hansen, 1922; Dana Stations), Northwest Atlantic (Yale Peabody Museum material, Dana material) Central Atlantic (Kr&oslash;yer, 1859), and South of Africa (Kensley, 1981; Dana material).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Vertical distribution:&lt;/i&gt; Recorded from the Dana stations 3000&ndash;5000-m wire corresponding to approximately 1000&ndash;1700 m of actual depth.&lt;/p&gt; &lt;p&gt; &lt;i&gt;PETALIDIUM SUSPIRIOSUM&lt;/i&gt; BURKENROAD, 1937&lt;/p&gt; &lt;p&gt;(FIGS 2C, 5A&ndash;D)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Petalidium suspiriosum&lt;/i&gt; Burkenroad, 1937: 325, figures 8&ndash;12. &ndash; Pearcy &amp; Forss, 1966: 1136&ndash;1137, 1140. &ndash; Wasmer, 1974:160, figures 1&ndash;8.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Material examined:&lt;/i&gt; Templeton Crocker Expedition, Zaca Station 165, T-3 (syntype, two appendages, YPM IZ 039178 and syntype, 1 f 7 mm, IZ 068756).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type material:&lt;/i&gt; Two syntypes of &lt;i&gt;Petalidium suspiriosum&lt;/i&gt;, Yale Peabody Museum (see above).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type locality:&lt;/i&gt; Gulf of California, 20.60&deg;N, 115.12&deg;W.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Diagnosis:&lt;/i&gt; Hepatic spine present; petasma with LAc (5&ndash;6 hooks) subequal to LA (9&ndash;11 hooks), LT bearing 0 and 2 hooks on branches; arthrobranchs on somite XIII dendritic.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Remarks:&lt;/i&gt; Both males and females of this species may be distinguished from the other species of the genus by the arthrobranchs above pereopod IV being dendritic. In addition, in males, the Lac is subequal to the LA (it is much more slender in &lt;i&gt;R. obesum&lt;/i&gt; and significantly more robust in &lt;i&gt;P. foliaceum&lt;/i&gt;). Also, the LA of &lt;i&gt;P. suspiriosum&lt;/i&gt; bears many more hooks (&gt; 8) than in other species. According to recent knowledge, any specimens found in the Pacific Ocean North of 20&deg;N belong to this species.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Geographical distribution (Fig. 7):&lt;/i&gt; Only found in the North Pacific between 20&deg;N and 52&deg;N: off Oregon (Pearcy &amp; Forss, 1966; Krygier &amp; Pearcy, 1981), off Hawaii (Walters, 1977), and off Japan (Kikuchi &amp; Omori, 1985). Specimens in the Oregon State University, Department of Oceanography collections have been taken as far north as 51&deg;40.9&prime;N 138&deg;30.3&prime;W and as far south as 34&deg;23&prime;N 140&deg;46&prime;W (Wasmer, 1974). The most southerly capture record is that of the type locality, 20&deg;36&prime;N 115&deg;07&prime;W (Burkenroad, 1937), where specimens were evidently brought from the north by the cold California Current.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Vertical distribution:&lt;/i&gt; 750&ndash;1500 m (off Hawaii, Walters, 1977), 800&ndash;2000 m (Kikuchi &amp; Omori, 1985).&lt;/p&gt;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 pages 466-468, 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

Petalidium Spence Bate 1881

&lt;i&gt;PETALIDIUM&lt;/i&gt; BATE, 1881 &lt;p&gt; &lt;i&gt;Diagnosis:&lt;/i&gt; Carapace and abdomen smooth, rostrum as a small protrusion of carapace, acute; supraorbital spine absent; cornea well pigmented; stylocerite fixed; mandible with three-segmented palp; maxillipeds I&ndash;II each with well-developed endopod; maxilliped I with threesegmented endopod; maxilliped III seven-segmented, dactylus not subdivided; pereopods IV&ndash;V progressively decreasing in length, flat, six-segmented, lacking dactyli, two distal segments setose only on one margin; uropodal exopod setose for distal 20% of outer margin, with small tooth. Male clasping organ: well-developed, bearing numerous spatulate ordered spines on both inner margins, tubercle absent, replaced by long stout spine. Petasma: LA, Lac and LI developed, entire; LC rudimentary, without hooks; LT divided, PU short, bearing hook; PV elongate, armed with hooks. Photophores: dermal organs and organ of Pesta absent. Branchiae: pleurobranchs on somites VIII&ndash;XII, lamellar posterior arthrobranch on somite XII.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Type species:&lt;/i&gt; By monotypy, &lt;i&gt;P. foliaceum&lt;/i&gt; Bate, 1881 (Perez-Farfante &amp; Kensley, 1997: 191).&lt;/p&gt; &lt;p&gt;Type locality: off Marion Island, 46&deg;46&prime;S, 45&deg;31&prime;E, depth 2516 m. South of Australia, 47&deg;25&prime;S, 130&deg;22&prime;E, depth 3935 m.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Species:&lt;/i&gt; &lt;i&gt;Petalidium foliaceum&lt;/i&gt; Bate, 1881; &lt;i&gt;P. obesum&lt;/i&gt; (Kr&oslash;yer, 1859); &lt;i&gt;P. suspiriosum&lt;/i&gt; Burkenroad, 1937.&lt;/p&gt;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 466, DOI: 10.1111/zoj.12243, &lt;a href="http://zenodo.org/record/10106760"&gt;http://zenodo.org/record/10106760&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

Petalidium Spence Bate 1881

TAXONOMY OF &lt;i&gt;PETALIDIUM&lt;/i&gt; &lt;p&gt; The character dataset indicates the need of an emended diagnosis of the genus. For a deeper insight into the taxonomy of &lt;i&gt;Petalidium&lt;/i&gt;, we analyzed the data in the available literature, which included a total of 10 variable characters (see Supporting informartion, Appendix S4). Having summarized these data, we concluded that only four of these 10 characters are of taxonomic value: character 3 (hepatic spines), character 5 (arthrobranchs on somite XIII), character 7 (LA of petasma compared to Lac of petasma), and character 8 (LA of petasma; number of hooks). These four characters, along with others that we have defined, are used by us as diagnostic characters for species of &lt;i&gt;Petalidium&lt;/i&gt;, and for phylogenetic reconstructions.&lt;/p&gt;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 466, DOI: 10.1111/zoj.12243, &lt;a href="http://zenodo.org/record/10106760"&gt;http://zenodo.org/record/10106760&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