Microcope levissima Malyutina, 2008, sp. nov.
Creators: name: Malyutina, Marina V.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Munnopsidae
Microcope
Microcope levissima

description: Microcope levissima sp. nov. (Figs. 7–11)
Material examined
Holotype, male (1.1 mm), (ZMH K- 41426), ANDEEP III St. 153–7–S, 29 March 2005, 62º32.52’-31.31’ S 64º36.44’ -37.53’ W, 2014 m.
Paratypes (ZMH K- 41427): 2 preparatory females dissected for description, (1.2 and 1.3 mm), 1 juv. (0.8 mm) and 2 males (1.2 mm) dissected for description, same data as the holotype.
Additional material: ANDEEP I & II: 1 damage female (ZMH K- 41428), St. 41–3–E, 26 January 2002, 59º22.24’-22.57’ S 60º04.06’ W, 2370 m; 2 females dissected for description, 1 male (ZMH K- 41429), St. 114–4–S, 17 February 2002, 61º43.54’ S 60º44.21’-44.43’ W, 2921 m; 1 female (ZMH K- 41430), St. 140–8– S, 21 March 2002, 58º15.98’-16.28’ S 24º53.73’ -54.09’ W, 2970 m.
Etymology. levissima refers to the smooth anterior margins of pereonites 1–4 of the species.
Description. Body (Figs 7, 8) length 1.7–1.9 width, body highest on ambulosome, height 0.35–0.4 of body length. Head length 0.2 width, antennulae inserted almost without gap in-between; clypeus 1.8 as wide and as long as labrum. Pereonites 1–2 subequal in length, pereonite 4 shortest, length about 0.3 pereonite 1 length; anterolateral margin of pereonites 1–4 smooth, pereonites 2–4 anterolateral projections moderately protruding, coxae anterior lobe more or less rounded, lateral margin of coxa with 3 setae. Natasome length 0.85 body length, width 1.6–1.8 head width; pereonite 5 lateral length 1.7–1.8 lateral length of pereonites 6 and 7 together. Pleotelson length 0.85 width, 0.35 body length, pleopodal cavity width 0.45 of pleotelson width, length 0.5 pleotelson length.
Antennula (Fig. 10) 0.4 of body length; article 1 length 1.1 width, with 3 short lateral setae, distomedial lobe with 1 long and 3 short distal robust setae; article 2 length 0.5 of article 1, with 2 distal broom and 2 simple setae; article 3 length 0.8 of article 2, flagellum of 4 articles, article 4 length 0.25 article 3 length, following two articles as long as article 3, last two articles slightly shorter than preceding, with 3 aesthetasc.
Antenna incomplete on all specimens (Figs 7, 8): article 1 shortest, articles 2–4 subequal in length, with ventrodistal stout setae, scale on article 3 with 4 distal setae.
Mandibles (Fig. 9) pars incisiva with 5 cusps; lacinia mobilis of left mandible slender, about as long as pars incisiva, with 4 teeth; spine row with 4 and 5 spines on left and right mandibles respectively; condyle length 0.3 molar length; palp strong, length 1.3 mandibular body length, width equal to molar process width, article 1 with 2 long distal setae, article 2 length 1.7 article 1 length, with 4 distal setae. Maxilla 1 (Fig. 9) lateral endite 1.2 width of mesial endite. Maxilla 2 (Fig. 9) mesial endite shortest, lateral endites longest, like middle endite with 2 long and 2 short distal setae. Maxilliped (Fig. 9) basis length 2.6 width, endite with 2 coupling hooks, distal margin with numerous simple and serrated slender setae; palp article 2 lateral margin straight, with 2 long whip setae, length 1.3 length of medial margin, article 3 medial length 3 times lateral length, distal half of medial margin dentate, with few setae; articles 3 and 4 subequal in lateral length, article 5 1.5 longer than article 4 laterally; medial lobe of article 4 broader and shorter than article 5, with 4 long distal setae, article 5 with 2 distal setae. Epipod slightly longer than basis, length 3 times width.
Pereopods (Fig. 10). Pereopod 1 length 0.5 body length, length ratios of ischium–dactylus to basis: 0.4, 0.2, 0.5, 0.5, 0.2; basis length 5.7 width, with sparse simple setae; ischium length 2.3 width, with 1 stout and 2 simple distodorsal setae and 2 ventral setae; merus length 1.3 width, with 2 distodorsal and 2 distoventral setae; carpus length 5.5 width, with 3 distodorsal and 4 ventral setae; propodus length 6 times width, with 3 distodorsal setae. Pereopods 2–4 incomplete on all specimens, basis length/width: 3.9, 3.5, 3 respectively.
Pereopods 5 and 6 (Fig. 10): carpus/propodus length ratios: 1.6, 1.4 for pereopods 5 and 6 respectively; carpus/propodus width ratios: 1.7, 1.5 for pereopods 5 and 6 respectively. Pereopod 5 length 1.2 pereopod 1 length, length ratios of ischium–dactylus to basis: 1.25, 0.5, 1.5, 1.1, 1.25; basis length 1.5 width, with few ventral setae; ischium length 2 times width, with 1 dorsal and 4 ventral simple setae; merus as long as wide, with 3 distal setae; carpus length 2.4 width, with 8 ventral and 12 dorsal setae; propodus length 2.7 width, with 7 ventral and 7 dorsal setae; dactylus length 11.3 width, claw length 0.15 dactylus length. Pereopod 6 length ratios of ischium–dactylus to basis: 1.5, 0.6, 1.8, 1.2, 1.3; basis length 2.5 width, with 2 distoventral setae; ischium length 2.6 width, with 4 stout distal setae; merus length 1.1 width, with 2 distoventral and 2 distodorsal setae; carpus length 2.7 width, with 11 ventral and 11 dorsal setae; propodus and dactylus similar in shape and size to those of pereopod 5.
Pleopods (Fig. 11): Male pleopod 1 length 3.1 width, distolateral margin with 3 plumose setae; distal margin: medial lobes rounded, slightly longer and 3.5 wider than lateral lobes, each with 6–8 distal setae. Pleopod 2 protopod length 3.6–3.8 width, distolateral margin with 7–8 setae, stylet length subequal to protopod length, sperm duct opened at midlength of stylet; exopod stout, as wide as basal article of endopod, 0.2 of protopod length. Pleopod 3 protopod as long as endopod, endopod length 2.3 of proximal width and 1.3 width of distal part, exopod 1.6 length and same width as endopod, with 3–4 lateral plumose and many thin simple setae, distal article weakly separated. Pleopod 4 endopod length 1.8 width, exopod as long as endopod, distal plumose seta longer than exopod. Pleopod 5 length 1.8 width. Female pleopod 2 (Fig. 8) length 1.45 width, distal truncate margin about as wide as proximal edge.
Uropod (Fig. 7) length 0.15 pleotelson length. Protopod length 2.7 width, medial extension after endopod insertion 0.3 of protopod length; endopod length 0.9 protopod length, with 2 stout, 2 broom and 4 simple distal setae; exopod 0.5 of endopod length and width, with 6 distal setae.
Remarks. Minicope levissima sp. nov. is similar to M. denticulata sp. nov., but can be distinguished from the latter by the following characters: smooth anterior margin of pereonites 1–4 (the margin is serrated in M. denticulata); the distance between antennulae in M. levissima is smaller than that in M. denticulata; the coxae of pereopods 1–4 are less acute and more rounded, whereas in M. denticalata they are larger and more acute. The female pleopod 2 of M. levissima has a broader distal margin than that of M. denticulata; the uropod protopod of M. levissima has a shorter distomedial extension than that of M. denticulata.
Distribution: The species is only known from the type locality. Compared to the bathymetric distribution of the two other species of the genus, this species is known from the shallowest location, occurring in depths between 2014 and 2970 m.
Acknowledgements
I am very grateful to Prof. Dr. Angelika Brandt and Dr. Nils Brenke for the opportunity to work with the ANDEEP and DIVA material. I would like to thank Dr. Saskia Brix and the organizing team of CeDAMar, especially Prof. Dr. Pedro Martnez Arbizu for carrying out the Workshop on deep-sea Isopoda at the DZMB (German Centre for Marine Biodiversity Research), Wilhelmshaven. I am thankful to Dr. Nils Brenke and anonymous reviewer for their corrections and comments leading to an improved manuscript. Stefanie Kaiser kindly checked and corrected the English.
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description: Published as part of Malyutina, Marina V., 2008, Microcope gen. nov. — a new deep-sea genus of Munnopsidae (Crustacea, Isopoda, Asellota), with description of two new species from the Southern Hemisphere, pp. 555-574 in Zootaxa 1866 on pages 567-574, DOI: 10.5281/zenodo.183860