Understanding the Function of a Target Gene in Fat Cell Development and Its Potential to Combat Obesity

Author Institution (all): Department of Animal Sciences, The Ohio State Universit

Membrane-bound delta-like 1 homolog (Dlk1) promotes while soluble Dlk1 inhibits myogenesis in C2C12 cells

AbstractDelta-like 1 homolog (Dlk1) is important in myogenesis. However, the roles of different Dlk1 isoforms have not been investigated. In C2C12 cell lines producing different Dlk1 isoforms, membrane-bound Dlk1 promoted the hypertrophic phenotype and a higher fusion rate, whereas soluble Dlk1 inhibited myotube formation. Inversed expression patterns of genes related to myogenic differentiation further support these phenotypic changes. In addition, temporal expression and balance between the Dlk1 isoforms have a regulatory role in myogenesis in vivo. Collectively, Dlk1 isoforms have distinctive effects on myogenesis, and its regulation during myogenesis is critical for normal muscle development

Greater numbers and sizes of muscle bundles in the breast and leg muscles of broilers compared to layer chickens

Meat-type (broiler) and egg-type (layer) chickens were bred by intensive selection over the years, resulting in more numbers and larger sizes of myofibers. Although the characteristics are important parameters in muscle growth and meat quality, muscle bundle characteristics have not been studied in poultry. Therefore, this study aimed to compare the histological characteristics of myofibers and muscle bundles in muscles between male broiler (Ross broiler breed) chickens and layer (Hy-Line) chickens. Chicken muscles, pectoralis major (PM) and gastrocnemius (GM), were sampled at the age of 49 days and stained to analyze histological characteristics. Expectedly, body weights (BWs) and weights of PM and GM muscles in 49-day-old broilers were significantly heavier than those in layers. Within PM, broilers exhibited greater number and cross-sectional area (CSA) of myofibers than layers (3.3- and 3.3-fold, respectively). The total number and CSA of PM muscle bundles were approximately 1.5 and 6.6 times greater, respectively, in broilers than layers. Moreover, broilers exhibited 2 times greater number of myofibers per bundle of PM muscle than layers. Within GM, myofiber number and CSA were 2.3- and 2.4-fold greater, respectively, in broilers than layers. In addition, the total number of muscle bundles and bundle CSA were 2.5- and 2.1-fold greater, respectively, in broilers than in the layers. The novel findings of the current study provide evidence that greater muscle mass of broilers occurs by both hyperplasia and hypertrophy of muscle bundles and myofibers

A functional regulatory variant of MYH3 influences muscle fiber-type composition and intramuscular fat content in pigs

Muscle development and lipid accumulation in muscle critically affect meat quality of livestock. However, the genetic factors underlying myofiber-type specification and intramuscular fat (IMF) accumulation remain to be elucidated. Using two independent intercrosses between Western commercial breeds and Korean native pigs (KNPs) and a joint linkage-linkage disequilibrium analysis, we identified a 488.1-kb region on porcine chromosome 12 that affects both reddish meat color (a*) and IMF. In this critical region, only the MYH3 gene, encoding myosin heavy chain 3, was found to be preferentially overexpressed in the skeletal muscle of KNPs. Subsequently, MYH3-transgenic mice demonstrated that this gene controls both myofiber-type specification and adipogenesis in skeletal muscle. We discovered a structural variant in the promotor/regulatory region of MYH3 for which Q allele carriers exhibited significantly higher values of a* and IMF than q allele carriers. Furthermore, chromatin immunoprecipitation and cotransfection assays showed that the structural variant in the 5-flanking region of MYH3 abrogated the binding of the myogenic regulatory factors (MYF5, MYOD, MYOG, and MRF4). The allele distribution of MYH3 among pig populations worldwide indicated that the MYH3 Q allele is of Asian origin and likely predates domestication. In conclusion, we identified a functional regulatory sequence variant in porcine MYH3 that provides novel insights into the genetic basis of the regulation of myofiber type ratios and associated changes in IMF in pigs. The MYH3 variant can play an important role in improving pork quality in current breeding programs

A functional regulatory variant of MYH3 influences muscle fiber-type composition and intramuscular fat content in pigs

Muscle development and lipid accumulation in muscle critically affect meat quality of livestock. However, the genetic factors underlying myofiber-type specification and intramuscular fat (IMF) accumulation remain to be elucidated. Using two independent intercrosses between Western commercial breeds and Korean native pigs (KNPs) and a joint linkage-linkage disequilibrium analysis, we identified a 488.1-kb region on porcine chromosome 12 that affects both reddish meat color (a*) and IMF. In this critical region, only the MYH3 gene, encoding myosin heavy chain 3, was found to be preferentially overexpressed in the skeletal muscle of KNPs. Subsequently, MYH3-transgenic mice demonstrated that this gene controls both myofiber-type specification and adipogenesis in skeletal muscle. We discovered a structural variant in the promotor/regulatory region of MYH3 for which Q allele carriers exhibited significantly higher values of a* and IMF than q allele carriers. Furthermore, chromatin immunoprecipitation and cotransfection assays showed that the structural variant in the 5′-flanking region of MYH3 abrogated the binding of the myogenic regulatory factors (MYF5, MYOD, MYOG, and MRF4). The allele distribution of MYH3 among pig populations worldwide indicated that the MYH3 Q allele is of Asian origin and likely predates domestication. In conclusion, we identified a functional regulatory sequence variant in porcine MYH3 that provides novel insights into the genetic basis of the regulation of myofiber type ratios and associated changes in IMF in pigs. The MYH3 variant can play an important role in improving pork quality in current breeding programs.info:eu-repo/semantics/publishedVersio

A new species of Harpacticella Sars, 1908 (Copepoda, Harpacticoida), from a tidal pool on Jeju Island, Korea

A new species of the genus Harpacticella Sars, 1908 is described from a tidal pool on Jeju Island, Korea. Harpacticella jejuensis sp. n. is closely related to H. itoi Chang & Kim, 1991, with regard to the structure of P1 exp-1 and enp-1, the length of P1 exp-1 and exp-2, and the setal number of the P5 exopod in males. However, the new species is clearly distinguishable from H. itoi by the combined following characters: six setae on the P5 exopod in females, one naked seta on the inner margin of P1 exp-2, the short endopod of P1 compared to the exopod, and a naked long seta on the proximal inner margin of the P5 exopod of males. The mtCOI partial sequence is provided as a DNA barcode for the new species

Research Note: Distribution of nanospheres in the cuticle layer of the eggshell in major poultry species

ABSTRACT: Mineralized eggshell is a unique and protective structure in an avian egg. Among different eggshell layers, the cuticle layer is an outermost layer and plays a critical role in protection against bacterial infection. Although the importance of nanosphere in the cuticle layer on the antimicrobial function has been widely accepted, the detailed nanostructure of the cuticle layer in the major poultry species has not been investigated. In the current study, eggs from Japanese quail, commercial layer chickens, mixed breed turkeys, and White Pekin ducks were collected. To investigate the nanostructure throughout the cuticle layer, images of the cross-sectional cuticle layer were taken using a scanning electron microscope (SEM). Unlike the cuticle layer in ducks showing deformed bunched nanospheres, clearly separated nanospheres were present throughout the cuticle layer in quail, chickens, and turkeys. The average size of the nanosphere was the biggest in turkeys and similar between quail and chickens. Most importantly, the size of nanospheres was increased as they ascended from the bottom of the cuticle layer in quail, showing a positive correlation between the size and distance of the nanospheres. However, different sizes of nanospheres were randomly distributed throughout the cuticle layer in chickens and turkeys, showing a weak correlation in chickens and no correlation in turkeys between the size and distance of nanospheres. These new findings in different nanostructures of the cuticle layers in quail, chickens, turkeys, and ducks will serve as a new foundation to better relate their structures with functions

Enhydrosoma kosmetron Karanovic, Kim & Lee, 2015, sp. nov.

<i>Enhydrosoma kosmetron</i> sp. nov. <p>(Figs. 16–21)</p> <p> <b>Type locality.</b> South Korea, South Sea, Gwangyang Bay, sampling station 3 (see Karanovic <i>et al.</i> 2014), muddy sediments, 3453'03.9" N 12739 '50.5"E.</p> <p> <b>Specimens examined</b>. Holotype female (NIBRIV 0000287224) dissected and mounted on one slide, collected from the type locality, 17 February 2013, collected by K. Kim. Allotype male (NIBRIV 0000287225) dissected and mounted on one slide, collected from Korea, South Sea, Gwangyang Bay, sampling station 10 (see Karanovic <i>et al.</i> 2014), 34°55'15.4"N 127°47'07.9"E, 18 February 2012, collected by K. Kim. Additional paratypes: one dissected female (NIBRIV 0000287226) mounted on one slide; four males and two females together on one SEM stub (NIBRIV 0000287227); three males and three females together on another SEM stub (NIBRIV 0000287228); all from Korea, South Sea, Gwangyang Bay, sampling station 10 (see Karanovic <i>et al.</i> 2014), 34°55'15.4"N 127°47'07.9"E, 18 February 2012, collected by K. Kim. One female used for molecular analysis collected by K. Kim from the type locality on 26 July 2012 (see Table 1).</p> <p> <b>Etymology.</b> This species is named after the Greek noun <i>kosmetron,</i> meaning “broom” and referring to the broom-like ornamentation of the male antennulae. The specific name is to be treated as a noun (gender masculine) in apposition to the generic name.</p> <p> <b>Description of female.</b> Based on holotype and several paratypes. Total body length from 441 to 495 µm (mean = 483 µm, n = 7). Body segmentation, colour, nauplius eye, hyaline fringes, general integument thickness, angle between telescoped and non-telescoped parts of pleurons on most free somites, and most somite ornamentation as in <i>Enhydrosoma apimelon</i> <b>sp. nov.</b>, however, surface relief on most somites slightly different. Habitus (Figs. 16 A) generally cylindrical in dorsal view, widest at posterior end of cephalothorax and tapering posteriorly, boundary between prosome and urosome inconspicuous; prosome/urosome length ratio about 1.1, and prosome only slightly more voluminous than urosome. Body length/width ratio about 3.7 in dorsal view; cephalothorax about 1.2 times as wide as genital double-somite. Free pedigerous somites without lateral or dorsal expansions, heavily sculptured, pleurons only partly covering coxae of swimming legs in lateral view. Integumental relief more defined by ridges than depressions in dorsal and lateral view; ventro-lateral ridges on urosomites as in <i>E. apimelon</i>, but ventral surface with additional (mostly internal) ridges. Most cuticular depressions and posterior margin of prosomites without hair-like spinules but full of bacterial growth and detritus, making observation of cuticular pores and sensilla in those regions very difficult; posterior margin of urosomites with hair-like spinules, especially on ventral surface. Hyaline fringe of all somites narrow and rough, in some places nearly serrated, and in all but last two somites also with conical mound-looking protuberances with sensilla on tip, as in <i>E. apimelon</i>. In addition to hairlike spinules, surface ornamentation of somites and caudal rami consists of at least two different types of sensilla (slender and bottle-shaped; see Fig. 16 C), simple cuticular pores, and few stronger spinules; exact number of pores and spinules difficult to establish.</p> <p> Rostrum (Fig. 16 B, E) as in <i>E. apimelon,</i> except for space between sensilla smaller than width of one horn-like projection.</p> <p> Cephalothorax (Fig. 16 B) as in <i>E. apimelon</i>, but with completely different relief in dorsal view, without oval depression and with more pronounced longitudinal ridges (compare Figs. 3 B and 16B), without comb of long setules in anterior part along inner surface of lateral margin (as observed in <i>E. apimelon</i>) or ventral flaps that protect first three pairs of mouth appendages (as observed in <i>E. robustum</i> <b>sp. nov.</b>); lateral relief similar to that in <i>E. apimelon</i>, except for posterior depression larger and more triangular; most sensilla easy to homologize.</p> <p> Pleuron of free prosomites (Fig. 16 A) very similar to each other, without triangular dorsal plates and posterior hair-like spinules, but with posterior conical mound-looking protuberances at base of sensilla, as well as dorsal and dorso-lateral ridges similar to those in <i>E. apimelon</i> but slightly smaller; all sensilla homologous to those in <i>E. apimelon</i>; angle between telescoped and non-telescoped parts of pleuron relatively wide as in <i>E. apimelon</i>.</p> <p>First urosomite (Fig. 16 A) slightly narrower and significantly longer than fourth pedigerous somite and pleuron without free lateral margin, but relief very similar to that of other pedigerous somites, with pronounced dorso-lateral ridges resulting in angular shape in cross-section.</p> <p> Genital double-somite (Figs. 16 A, 19A) 1.6 times as wide as long in ventral view; completely fused ventrally but with deep suture indicating original segmentation between genital and third urosomites dorsally, thus dividing double-somite into equally long and similarly wide halves; general shape and ornamentation as in <i>E. apimelon</i>, except for more pronounced ridges on ventral surface and additional pair of ventral pores. Female genital complex (Fig. 19 A) weakly sclerotized and hardly distinguishable from internal sutures and soft tissue, except for large copulatory pore near midlength of somite and wide copulatory duct; genital operculum as in <i>E. apimelon</i> but with longer armature elements and shorter spinules.</p> <p>Third urosomite (Figs. 16 A, 19A) very similar in shape and ornamentation to posterior part of genital doublesomite, but without ventral pores and with three or four large spinules on ventral surface at base of each ventral sensillum.</p> <p>Fourth urosomite (Figs. 16 A, D, 19A) slightly shorter and narrower than third urosomite and without any sensilla and large spinules, but with well-developed dorsal, dorso-lateral, and ventro-lateral ridges (latter finely serrated), with posterior row of hair-like spinules, and with ventro-lateral cuticular pores.</p> <p> Anal somite (Figs. 16 A, D, 19A, B) only slightly clefted medially, with one pair of large dorsal sensilla at base of anal operculum, several minute spinules, small group of large ventral spinules on medial corners, and one pair of ventral simple pores; ventro-lateral corners produced as in preanal somite, but slightly longer and more flared out, also serrated; dorso-lateral corner also produced into small serrated flaps; anal operculum (Figs. 16 D, 19B) semicircular, short, not reaching posterior margin of somite (shorter than in <i>E. apimelon</i> but longer than in <i>E. robustum</i>), serrated, representing 39% of somite's width; anal sinus widely open, with three rows of hair-like spinules.</p> <p> Caudal rami (Figs. 16 A, D, 19A, B) spindle-shaped, widest at about proximal quarter of their length, about 1.4 times as long as anal somite, about 2.2 times as long as wide (ventral view), strongly divergent, with strong dorsal ridge, and with space between them about one ramus’ width. Armature as in <i>E. apimelon</i> but dorsal seta longer and inserted more posteriorly (at about midlength); ornamentation as in <i>E. robustum</i>; no tubular pore at base of anterior lateral setae; outer distal process carrying posterior lateral seta even more produced than in <i>E. robustum</i>; proportion of setae other than dorsal similar to that in <i>E. apimelon</i>; principal apical seta 1.3 times as long as ramus.</p> <p> Antennula (Figs. 16 F, 20A) as in <i>E. apimelon</i>, except for second segment with one seta less (thus armature formula being: 1.8.7+ae.1.11+ae), and five additional spiniform setae and with strong spinules (three setae on second segment, one on third segment, and stronger apical seta on fifth segment). Lnegth and ornamentation of segments as in <i>E. apimelon</i>; as in <i>E. apimelon</i> and <i>E. robustum</i> one unipinnate slender seta on second segment inserted into cone-shaped depression.</p> <p> Antenna (Figs. 19 C), labrum, paragnaths, general shape and armature of maxilla (Fig. 20 B), maxilliped (Fig. 20 C), endopod of first swimming leg (Fig. 20 D), second swimming leg (Fig. 20 F), exopod of third swimming leg, and exopod of fourth swimming leg as in <i>E. apimelon</i> and <i>E. robustum,</i> except for small differences in proportion of certain segments and armature elements and very minor differences in ornamentation.</p> <p> Mandibula (Fig. 19 D) size and segmentation as in <i>E. apimelon</i>, but palp with four setae and seta on cutting edge of coxal gnathobase much stronger and longer.</p> <p> Maxillula (Fig. 19 E) size and segmentation as in <i>E. apimelon</i>, but both basis and praecoxal arthrite with one additional inner seta.</p> <p> Maxilliped (Fig. 19 C) as in <i>E. apimelon</i>, except endopodal strong spine shorter and slender endopodal seta proportionately longer; coxa ornamented with three rows of spinules.</p> <p>Exopod of first swimming leg (Fig. 20 E) with five elements on third segment.</p> <p>Endopod of third swimming leg (Fig. 20 G) and endopod of fourth swimming leg (Fig. 20 H) both with very short outer spines in addition to two slender and long terminal setae on second segment.</p> <p> Fifth leg (Fig. 20 I) biramous as in <i>E. apimelon</i>, comprising conical exopod and baseoendopod, but exopod much more robust and endopodal lobe shorter; exopod also armed with three elements, but lateral elements inserted closer to distal margin (as in <i>E. robustum</i>), with distal lateral element almost apical and difficult to homologize, and apical element very small and bare. Outer margin of exopod with numerous long hair-like spinules, inner margin smooth, without tubular pores; baseoendopod as in <i>E. robustum</i> with robust distal seta, but with only one cuticular spiniform process on inner margin covered by small spinules; distal exopodal element about 0.3 times as long as proximal endopodal spine, 0.2 times as long as distal endopodal spine, 0.75 times as long as proximal exopodal element, 0.25 times as long as middle exopodal element, 0.3 times as long as distal endopodal element, and less than 0.2 times as long as entire exopod; exopod about 3.3 times as long as wide. Endopodal lobe without tubular pores, but with two simple pores at base of inner spines.</p> <p> Sixth legs (Fig. 19 A) as in <i>E. apimelon</i>, but with proportionately smaller basal spinules and larger armature; inner smooth seta about 1.7 times as long as outer unipinnate spine.</p> <p> <b>Description of male.</b> Based on allotype and four other paratypes. Body length ranging from 279 to 312 Μm (mean = 302 µm, n = 5). Genital somite and third urosomite not fused (Fig. 19 F). Habitus (Figs. 16 G, 17A, 18A), colour, rostrum, shape and ornamentation of cephalothorax (Fig. 18 B, C, D), shape and ornamentation of free prosomites (Fig. 16 G, 18A), shape and ornamentation of last three urosomites (Figs. 16 H, 17C, H, 18H, 19F), general shape, armature and ornamentation of caudal rami (Figs. 16 H, 17C, 18H, 19F), antenna (Fig. 17 E), labrum (Fig. 17 F), paragnaths (Fig. 17 F), mandibula (Figs. 17 F, 21C, D), maxillula (Fig. 17 F, 21E), maxilla (Fig. 17 B, F), maxilliped (Fig. 17 F), first swimming leg (Fig. 17 G), second swimming leg (Fig. 17 A), exopod of third swimming leg (Fig. 17 A), and fourth swimming leg (Fig. 21 G) as in female. Prosome/urosome ratio about 1.2, greatest width at posterior end of cephalothorax, body length/width ratio about 3.3; cephalothorax 1.6 times as wide as genital somite in dorsal view.</p> <p> Genital somite (Figs. 17 H, 19F) 1.8 times as wide as long in ventral view, similar in ornamentation to that in <i>E. robustum</i>, and also with left sixth leg functioning as genital operculum; no spermatophore visible inside any observed specimens.</p> <p>Third urosomite (Figs. 17 H, 19F) as posterior part of genital double-somite in female but proportionately narrower, and with four or five large ventro-lateral spinules.</p> <p>Caudal rami (Figs. 16 H, 17C, 19F) very similar to those in female but slightly longer in proportion to anal somite and more robust.</p> <p> Antennula (Figs. 17 D, 18E, F, G, 21A, B) as in <i>E. apimelon</i>, except for second segment with two spiniform setae, third segment with one spiniform seta, fourth segment with large broom-like structure instead of brush and with only six or seven large spinules, fifth segment with large spiniform process and three slender setae, and sixth segment with large characteristically shaped tube pore (Fig. 18 G); second segment as in female with slender plumose seta inserted into cone-like depression (Fig. 18 F).</p> <p>Endopod of third swimming leg (Fig. 21 F) transformed and apparently three-segmented, with outer spine fused to segment and enlarged, secondary segmentation resulting in very small third segment bearing two long and slender apical setae.</p> <p>Fifth leg (Figs. 17 H, 21H) somewhat smaller than in female but with similar basic structure; exopod about 2.3 times as long as wide, with all three elements present and of similar proportions as in female, except for apical one bipinnate; endopodal lobe without distal armature element or inner spiniform processes, its distal tip with bunch of hair-like spinules; proximal endopodal inner spine about 1.6 times as long as distal endopodal inner spine and 1.2 times as long as longest element on exopod.</p> <p> Sixth legs (Figs. 17 H, 19F) as in <i>E. robustum</i>, withsimple cuticular plates, unarmed, with transverse row of slender spinules.</p> <p> <b>Variability.</b> Despite numerous examined specimens and detailed examination using SEM (see Figs. 16 A, G, 17A, 18A), we are not able to report on any significant morphological variability. The number of ventro-lateral spinules on fourth male and female urosomite and third male urosomite varies between three and five.</p>Published as part of <i>Karanovic, Tomislav, Kim, Kichoon & Lee, Wonchoel, 2015, Concordance between molecular and morphology-based phylogenies of Korean Enhydrosoma (Copepoda: Harpacticoida: Cletodidae) highlights important synapomorphies and homoplasies in this genus globally, pp. 451-496 in Zootaxa 3990 (4)</i> on pages 477-486, DOI: 10.11646/zootaxa.3990.4.1, <a href="http://zenodo.org/record/245656">http://zenodo.org/record/245656</a&gt

Enhydrosoma apimelon Karanovic, Kim & Lee, 2015, sp. nov.

<i>Enhydrosoma apimelon</i> sp. nov. <p>(Figs. 1–9)</p> <p> <b>Type locality.</b> South Korea, South Sea, Gwangyang Bay, sampling station 10 (see Karanovic <i>et al.</i> 2014), muddy sediments, 3455'15.4" N 12747 '07.9"E.</p> <p> <b>Specimens examined</b>. Holotype female (NIBRIV 0000287210) preserved in 70% ethanol. Paratypes: two males and three females (NIBRIV 0000287211) preserved in 70% ethanol; one dissected female (NIBRIV 0000287212) mounted on nine slides; one dissected male (NIBRIV 0000287213) mounted on nine slides; one male and 12 females together on one SEM stub (NIBRIV 0000287214); three males and three females together on another SEM stub (NIBRIV 0000287215); collected on 8 December 2012 by K. Kim. One male and two females used for molecular analyses were collected by K. Kim on 8 December 2012 and 26 April 2012, respectively (see Table 1).</p> <p> <b>Etymology.</b> The species name derives from the Greek adjective <i>apimelos,</i> meaning “slender”, “without fat”, “lean”, and refers to the slender shape of the caudal rami. It was treated as an adjective, agreeing in gender with the neuter generic name.</p> <p> Species Cοde Sex Cοuntry Lοcality Statiοn Cοοrdinates Date Bases GenBank <b>Description of female.</b> Based on holotype and several paratypes. Total body length, measured from anterior margin of rostrum to posterior margin of caudal rami, from 291 to 335 µm (mean = 309 µm, n = 10). Colour of preserved specimens yellowish; live specimens not observed. Nauplius eye not visible. Prosome comprising cephalothorax with completely fused first pedigerous somite, and three free pedigerous somites; urosome comprising first urosomite (= fifth pedigerous somite), genital double-somite (fused genital and third urosomites) and three free urosomites (last one being anal somite). No sclerotized joint between prosome and urosome. Habitus (Figs. 1 A, 2A, 3A) almost cylindrical in dorsal view, widest at posterior end of cephalothorax and tapering posteriorly, boundary between prosome and urosome inconspicuous; prosome/urosome length ratio about 1.3, and prosome only slightly more voluminous than urosome. Body length/width ratio close to 3.5 in dorsal view; cephalothorax only about 1.3 times as wide as genital double-somite. Free pedigerous somites without lateral or dorsal expansions but heavily sculptured; pleurons only partly covering coxae of swimming legs in lateral view. Integument of all somites strongly sclerotized, generally very rough, without discernible cuticular windows or pits, but with characteristic relief of numerous surface ridges and depressions; majority of cuticular depressions and posterior margin of somites covered by dense hair-like spinules, bacterial growth, and detritus, making observation of cuticular pores and sensilla in those regions very difficult. Hyaline fringe of all somites narrow and rough. In addition to hair-like spinules, surface ornamentation of somites and caudal rami consisting of at least two different types of sensilla (slender and bottle-shaped), simple cuticular pores, tubular pores, and few large spinules; exact number of pores and spinules difficult to establish.</p> <p>Rostrum (Figs. 1 B, 3B, E) small, fused to cephalic shield, dorsally recurved in lateral view, bifid at tip, bearing two sensilla between apical horn-like projections, pore located on ventral side; space between sensilla greater than width of one apical horn.</p> <p>Cephalothorax (Figs. 1 B, C, 2H, 3B) tapering anteriorly in dorsal view, about as long as wide; comprising 30% of total body length. Surface of cephalic shield with at least 19 pairs of large sensilla (not counting those on rostrum), of those four pairs along posterior margin on conical mound-looking protuberances and four pairs along lateral margin. Majority of dorsal sensilla in depressions, majority of lateral sensilla on ridges. Interior surface of lateral margin of cephalic shield with characteristic comb of long setules in anterior part (Fig. 2 H), touching basis of antenna. Lateral surface of cephalic shield with two large semi-circular depressions, dorsal surface with three central and six paired small and oval depressions; long and strong ridge separating dorsal and lateral depressions.</p> <p>Pleuron of second pedigerous somite (first free) (Figs. 1 A, B, 3A, B) with irregular and shallow relief, posterior margin with at least four pairs of sensilla on conical mound-looking protuberances and row of sparse hairlike spinules; ridge between lateral and dorsal side pronounced but not produced posteriorly; posterior lateral depression large, triangular.</p> <p>Third pedigerous somite (Figs. 1 A, 3A, C) slightly shorter than second pedigerous somite but of similar width; pleuron relief with two smooth dorsal triangles with sensilla on posterior tip, dorso-lateral ridges more pronounced than in second pedigerous somite and slightly produced posteriorly; low laying surface in between triangles and dorso-lateral ridges covered with dense pattern of small, hair-like spinules; posterior margin with at least three pairs of sensilla on conical mound-looking protuberances (in addition to dorsalmost pair on triangles) and row of sparse but long hair-like spinules.</p> <p>Fourth pedigerous somite (Figs. 1 A, 3A, C) similar in size, shape, relief and ornamentation to third pedigerous somite, with slightly more posteriorly produced dorso-lateral ridges and longer dorsal triangles.</p> <p>First urosomite (Figs. 1 A, 3A) slightly longer but not narrower than fourth pedigerous somite; pleuron without free lateral margin; relief similar to that of fourth pedigerous somite but with more pronounced dorso-lateral ridges and smaller and less clearly defined dorsal triangles; posterior margin with at least four pairs of sensilla.</p> <p>Genital double-somite (Figs. 1 A, 2A, C, 3A, 5A) 1.3 times as wide as long in ventral view; completely fused ventrally but with deep dorso-lateral suture indicating original segmentation between genital and third urosomites, thus dividing double-somite into equally long and similarly wide halves. Ventral surface relatively smooth, flat, with shallow relief but dorso-lateral and ventro-lateral ridges pronounced together with pronounced dorsal triangular structures result in almost hexagonal cross-section; dorso-lateral and ventro-lateral ridges significantly produced posteriorly, each bearing single large sensilla on tip. Two additional ventral and two dorsal sensilla visible on posterior margin, and at least three pairs of sensilla visible in anterior half; both anterior and posterior half with ventro-lateral pair of simple pores; posterior margin with row of hair-like spinules, and one ventral row of strong spinules in anterior half, at base of genital operculum. Female genital complex (Fig. 5 A) weakly sclerotized and hardly distinguishable from internal sutures and soft tissue, except large copulatory pore in posterior half and wide copulatory duct; genital aperture ventrally in proximal quarter, covered by reduced sixth legs acting as genital operculum.</p> <p>Fourth urosomite (third free) (Figs. 1 A, 2A, C, 3A, 5A) similar in shape and ornamentation to posterior part of genital double-somite, except narrower and with tubular ventro-lateral pores; posterior projections of ventro-lateral and dorso-lateral ridges long, each with apical sensilla.</p> <p>Fifth urosomite (preanal) (Figs. 1 A, F, G, H, 2A, 5A) shorter and narrower than third urosomite, with shorter posterior projections of dorso-lateral and ventro-lateral ridges, without sensilla, ornamented with pair of ventrolateral tubular pores, posterior row of long hair-like spinules, and several minute spinules on ventro-lateral ridge.</p> <p>Anal somite (Figs. 1 F, G, H, 2B, G, 3D, 5A, B, C) clefted medially in posterior fifth, with one pair of large dorsal sensilla at base of anal operculum, one pair of lateral tubular pores, one pair of ventral tubular pores, and several stronger terminal spinules. Dorso-lateral and medial corners produced into small serrated flaps; anal operculum (Fig. 3 D) semi-circular, long, wide, reaching beyond posterior margin of somite, strongly serrated, representing nearly half of somite's width. Anal sinus (Fig. 1 G, H) widely open, with one dorsal and two diagonal rows of long hair-like spinules.</p> <p>Caudal rami (Figs. 1 F, G, H, 2B, G, 3D, 5A, B, C) long, slender, about twice as long as anal somite, widest at base, gently tapering posteriorly, about 3.2 times as long as wide (ventral view), slightly divergent and nearly cylindrical, separated by distance of about ramus width; armature consisting of seven setae (three lateral, one dorsal, three apical). Ornamentation consisting of lateral tubular pore and numerous hair-like spinules on all sides, those on inner margin anteriorly especially long (see Fig. 2 B), those on outer posterior corner forming dense tuft (Fig. 1 G); dorsal seta (Fig. 2 G) smooth, slender, inserted close to inner margin at about first quarter of ramus’ length, approximately half as long as caudal ramus, triarticulate at base (i.e. inserted on two pseudojoints); two proximal lateral setae smooth, of equal length, 0.24 times as long as ramus, inserted very close to each other at about two fifths of ramus length, very close to lateral tubular pore. Ancestral distal lateral seta also smooth, only slightly longer than proximal lateral setae, inserted on outer posterior corner of caudal ramus, flanked by tuft of spinules; inner apical seta smooth and very slender, about as long as proximal lateral setae. Principal apical setae fused basally, both without breaking planes and sparsely pinnate; middle apical seta much stronger and longer, about 3.7 times as long as outer apical one and 1.2 times as long as caudal ramus.</p> <p>Antennula (Figs. 1 D, 3E, 6 A–H) short, stout, five-segmented, joined to cephalothorax with small triangular pseudo-segment, approximately half as long as cephalothorax, without cuticular processes, with three rows of strong spinules on first segment. Long aesthetasc on third segment relatively slender, fused basally with adjacent large seta, reaching slightly beyond tip of appendage; even more slender and much shorter apical aesthetasc on fifth segment fused basally with two apical setae, forming apical acrothek. Armature formula: 1.9.7+ae.1.11+ae. Seta on first segment, two setae on second segment, two setae on third segment, and three setae on fifth segment pinnate, all other setae smooth; one pinnate seta on third segment and all pinnate setae on fifth segment recurved, spiniform, with very strong spinules only along convex surface, all other setae slender; six lateral smooth setae on fifth segment biarticulate at base (i.e. inserted on small pseudojoint); dorsal seta on second segment inserted into funnelshaped depression. Length ratio of antennular segments, measured along caudal margin and from proximal end as:, 1: 4: 2: 0.6: 4.5.</p> <p>Antenna (Figs. 2 H, 6I) relatively short, composed of coxa, allobasis, one-segmented endopod and onesegmented exopod. Coxa short, with arched row of long posterior spinules. Allobasis longest and most robust segment of antenna, more than three times as long as coxa and about 1.1 times as long as endopod, widest at base and about 2.5 times as long as wide, unarmed, with several long spinules along inner (convex) margin in proximal half. Endopod about as wide as distal part of allobasis, almost cylindrical, about three times as long as wide, with two subdistal surface frills, and two diagonal rows of very large spinules on anterior surface; two strong, pinnate lateral spines flanking minute seta. Apical armature consisting of five elements: two stout but short unipinnate spines, two slender geniculate setae plus massive pectinate spine. Exopod short, forked distally, about as long as coxa but much narrower, with several slender spinules along outer margin, with two apical bipinnate setae; both exopodal setae slender, long, inner seta about 1.3 times as long as outer one, with longer spinules.</p> <p>Labrum (Fig. 2 H) large and complex tri-dimensional structure, trapezoidal in anterior view, rigidly sclerotized, with relatively wide, somewhat convex cutting edge, with subapical row of strong spinules and many apical rows of slender spinules and along posterior surface, additional short row of slender long spinules centrally on anterior surface.</p> <p>Paragnaths (Fig. 2 H) also forming complex tri-dimensional structure, trilobate, with two ellipsoid anterior lobes and one central posterior lobe, all fused at base, all lobes with numerous rows of slender anterior and apical spinules; posterior surface with single transverse row of extremely long spinules.</p> <p>Mandibula (Figs. 2 F, 7H) small, with narrow cutting edge on relatively long coxa, with two strong bicuspidate teeth ventrally, three unicuspidate teeth dorsally, and single dorsalmost slender and smooth seta; dorsalmost tooth longest, ventralmost tooth strongest; dorsal seta slightly shorter than dorsalmost tooth. Palp small, one-segmented, bifurcated distally, proximal half as long and wide as outer branch, inner branch much shorter; proximal part smooth, while each branch with long spinules on anterior surface; inner branch with single bipinnate apical seta, with very strong and long spinules; outer branch with two slender and sparsely bippinate apical setae; all palpal setae slender, subequally long, about 1.5 times as long as palp.</p> <p>Maxillula (Figs. 1 E, 2F, H, 8A) relatively small; praecoxa large, with two outer rows of spinules; praecoxal arthrite about as long as wide, with two large tube setae on anterior surface and four distal elements (three naked spines and one naked seta), transverse row of spinules on posterior surface. Coxa short, with two distal setae (one pinnate and one naked) and row of spinules on posterior surface; exopod and endopod fused to basis, as long as praecoxal arthrite but much more slender, with six naked setae and row of spinules on posterior surface.</p> <p>Maxilla (Figs. 1 E, 2F, H, 7I) small; syncoxa with three spinular rows on anterior surface and two endites; syncoxal proximal endite with one pinnate stout spine, one slender seta, and one tube seta Syncoxal distal endite similar to proximal endite, except slightly larger and tube seta shorter; basis with short row of spinules and one endite; basal endite with smooth spine distinct at base, tube seta on posterior surface, naked seta and short tubular pore distally.Endopod represented by two tubular setae fused basally.</p> <p>Maxilliped (Figs. 1 E, 2F, H, 8B) prehensile, three-segmented, composed of coxa, basis, and one-segmented endopod. Coxa slender, about twice as long as wide, cylindrical, unornamented, armed with single strong bipinnate seta on inner-distal corner. B basis largest and longest segment, about 2.2 times as long as wide and 1.6 times as long as coxa, with longitudinal row of slender inner spinules, unarmed. Endopod minute, subrectangular, apically with two one short and smooth and one smooth recurved claw; endopodal claw fused to endopod at base, 1.2 times as long as coxal seta and about 1.4 times as long as basis.</p> <p>All swimming legs (Figs. 1 A, 2A) of similar size, long in comparison to body length, composed of small triangular and unarmed praecoxa, large rectangular and unarmed coxa, shorter and nearly pentagonal basis, slender three-segmented exopod, and even more slender two-segmented endopod; none of exopods or endopods prehensile. Pairs of legs joined by simple intercoxal sclerite.</p> <p>First swimming leg (Figs. 3 F, 8C) with smooth, short intercoxal sclerite, distal margin slightly concave. Praecoxa subtriangular, shorter than intercoxal sclerite and about as long as coxa, ornamented with distal row of hair-like spinules on anterior surface. Coxa 2.5 times as wide as long, with longitudinal row of long outer spinules on anterior surface and another inner row of much smaller spinules, both without spinules along distal margin. Basis with one short but strong and finely bipinnate outer spine and one longer and stronger, also bipinnate inner spine, inner spine about 1.4 times as long as outer spine; ornamentation of basis consists of posterior row of very strong spinules, short row of more slender spinules at base of inner spine, and short row of strong spinules at base of outer spine, all on anterior surface. Exopod with all segments of about same length, each about 1.5 times as long as wide and with outer strong and very long spinules and subdistally on anterior surface and more slender spinules along inner margin; first and second exopodal segment each armed with single large outer spine, longer than segment; third exopodal segment with two strong and pinnate outer spines and two slender and very long apical setae; exopodal setae of about same length, 1.6 times as long as entire exopod, and about 2.6 times as long as distalmost exopodal spine, not prehensile, with short outer pinnules and long and sparse inner pinnules. Endopod 0.7 times as long as exopod, also with strong outer and slender inner spinules; first endopodal segment half as long as shortest exopodal segment, about as long as wide, unarmed; second endopodal segment slender, about 5.6 times as long as wide and 4.2 times as long as first endopodal segment, with one strong subapical outer spine, and long apical seta; apical endopodal seta slightly longer than apical exopodal setae, about three times as long as second endopodal segment, and 4.4 times as long as subapical endopodal spine.</p> <p>Second swimming leg (Fig. 8 D) similar to first swimming leg, except for shorter and wider intercoxal sclerite, without inner basal spine, first endopodal segment smaller, and second endopodal segment more slender and armed with two long setae.</p> <p>Third swimming leg (Fig. 9 A) similar to second swimming leg, except for more slender outer seta of basis, and third exopodal segment with additional inner slender seta.</p> <p>Fourth swimming leg (Fig. 9 B) as third swimming leg.</p> <p>Fifth leg (Figs. 2 C, D, E, 6J) biramous, comprising conical exopod and baseoendopod. Exopod longer than endopodal lobe and partly covered by it in ventral view, armed with two outer short spines and one longer apical spine, ornamented with several hair-like spinules and two tubular pores on anterior surface and distal frill on posterior surface. Baseoendopod armed with two inner strong spines, and one apical minute seta fused to several basal spinules, ornamented with numerous hair-like spinules on anterior surface and one long tubular pore at base of each inner spine; apical exopodal spine about 1.2 times as long as proximal endopodal spine, 1.4 times as long as distal endopodal spine, 2.4 times as long as either of outer exopodal spines, and nearly 0.6 times as long as entire exopod.</p> <p>Sixth legs (Fig. 5 A) fused into simple genital operculum, with row of strong spinules at its base; each leg armed with smooth inner seta and unipinnate outer spine; seta slightly longer than spine, both armature elements shorter than some spinules at base of sixth leg.</p> <p> <b>Description of male.</b> Based on five paratypes. Body length from 288 to 319 Μm (mean = 307 µm, n = 5). Genital somite and third urosomite not fused. Habitus (Figs. 3 G, 4A), colour, rostrum (Figs. 3 H, 4G), shape and ornamentation of cephalothorax (Figs. 3 G, H), shape and ornamentation of free prosomites (Fig. 3 G), shape and ornamentation of first urosomite (Fig. 3 G), general shape in dorsal view and most dorsal ornamentation of other urosomites (Fig. 3 G), general shape and armature of caudal rami (Figs. 3 G, 4B, 5D), antenna (Fig. 4 H), labrum, paragnaths, mandibula, maxillula, maxilla, maxilliped, and all swimming legs (Fig. 4 A) as in female. Prosome/ urosome ratio about 1.2, greatest width at posterior end of cephalothorax, body length/width ratio about 3.7; cephalothorax 1.5 times as wide as genital somite in dorsal view.</p> <p>Genital somite (Figs. 3 G, 4C, 5D) homologous to anterior part of genital double-somite in female but much narrower compared to other parts of urosome, 1.5 times as wide as long in ventral view, with all sensilla and pores homologous to those in female, no additional sensilla and pores observed; ventral surface without ridges or ornamentation, except spinules as base of sixth leg. Right sixth leg developed into genital operculum, while left sixth leg completely reduced, posterior short row of slender spinules as its only remnant; no spermatophore visible inside any examined specimens.</p> <p>Third urosomite (Figs. 3 G, 4C, 5D) homologous to posterior part of genital double-somite in female but proportionately much narrower, without ventro-lateral cuticular pores, and with ventral posterior row of very strong spinules.</p> <p>Fourth urosomite (Figs. 3 G, 4B, 5D) also narrower than in female, without tube on its ventro-lateral pores, and with medially interrupted ventral posterior row of very strong spinules.</p> <p>Fifth urosomite (Figs. 3 G, 4B, 5D) similar to that in f