Nannoniscus antennaspinis, Brandt, Angelika, 2002

Brandt, Angelika, 2002, New species of Nannoniscidae (Crustacea, Isopoda) and Saetoniscus n. gen. from the deep sea of the Angola Basin, Zootaxa 88, pp. 1-36: 28-35

publication ID

http://doi.org/ 10.5281/zenodo.155900

publication LSID

lsid:zoobank.org:pub:B99CFC86-E49D-43C9-9036-15D438F36CAE

persistent identifier

http://treatment.plazi.org/id/7B0F5E35-2647-FFEC-FA3D-FE9B322CFDC8

treatment provided by

Plazi

scientific name

Nannoniscus antennaspinis
status

n. sp.

Nannoniscus antennaspinis   n. sp. (Figs. 17­22)

Holotype female of 1.8 mm, ZMH, Nr. K­ 40110, station 348, 28.7 .2000, 16° 18.1 'S 05° 27.2 'E ­ 16 ° 19.3 'S 05° 27.2 'S, 5389 m.

Paratype male of 1.8 mm, ZMH, Nr. K­ 40111, station 348, 28.7 .2000, 16° 18.1 'S 05° 27.2 'E ­ 16 ° 19.3 'S 05° 27.2 'S, 5389 m.

Type locality: Angola Basin, Atlantic, 5389 m.

Distribution: only known from type locality.

Etymology: named for the long lateral spine on third peduncular article of antenna.

Description: habitus of holotype female illustrated in Fig. 17: Body dorsally smooth, without setae or elevations, and also without setules on lateral margins of pereonites and pleotelson. Lateral and caudal margins of pleotelson smooth, without spines or notches, lateral margins slightly rounded, laterocaudally acuminating after two thirds of length and extending into a rounded caudal apex. Cephalothorax broader than long, (Fig. 17), without rostrum, frontomedial margin of head straight, lateral margins of cephalon smooth and straight, eyes lacking; antennae inserting frontolaterally. Coxae not visible in dorsal view. Pereonites 1 ­ 4 only with slightly frontally directed laterofrontal margins, pereonite 1 very short, pereonites 2­4 increasing in length, 4 longest, pereonites 5­7 decreasing in length. Pleonites all fused with pleotelson. Pleotelson slightly broader than long.

Al article 1 (Fig. 17) rectangular, twice as long as broad, with 1 distal feather­like seta and two setae; article 2 1.4 times as long as first, with 3 lateral setae and 4 distal featherlike setae; article 3 shortest, ring­like, without setation. 2 flagellar articles, first one with acute spine­like projection, with 2 feather­like setae on top of this projection; last one bulbous, round oval, with 1 seta.

A 2 article 1 (Fig. 17) short, about triangular in shape, without setae; article 2 slightly longer than 1, with 1 seta; article 3 about as long as 1 and 2 together, with 1 medial seta and 1 long, produced lateral spine­like extension, bearing 1 seta; article 4 as long as one, with 1 medial seta; article 5 slightly longer than articles 1­4 together, with 4 setae and 1 feather­like distal seta; article 6 as long as 5, with 8 setae and one distal feather­like seta; flagellar article 1 ongest, as long as peduncular articles 1 and 2, with 2 setae; following 11 flagellar articles decreasing in width, with 1­3 setae, last article with 7 setae.

Mandibular palps comparably short, not reaching the distal tip of the pars incisiva, palp inserted proximally of mandibular body ( Fig. 18 View FIGURE 18 ), consisting of 3 articles; article 1 longest, with 1 simple distal seta in rMd, article 2 slightly shorter than 1, with 2 ventral setae, article 3 with 3 distal setae. Incisor of IMd with 5, of rMd also with 5 teeth, lacinia mobilis of IMd 5 teeth. Setal rows with 6­10 setae. Molars small, short, acuminating, bearing a tuft of 8 long, slightly serrated setae. RMd without lacinia mobilis.

Mxl lateral margin of inner endite (Fig. 17) without setae, distally with tuft of many slender setae. Tip of lateral endite with 11 serrated spines, medial margin without, outer margin with setules.

Mx 2 outer margins of lateral and inner endites ( Fig. 18 View FIGURE 18 ) with few long setules, inner margin of inner endite setose, with 2 rows of 5 fringed setae distally. 3 strong setae of varying lengths on lateral and medial endites.

Mxp epipod ( Fig. 18 View FIGURE 18 ) short, bare, reaching to mid of second palpal article. First palpal article short, rectangular, with 1 seta, second one 5 times as long as first, with 2 medial and 1 lateral setae, medial margin of the 3 rd palpal article with 3 setae on serrated margin; article 4 slightly longer than 1, half as wide as third, with 3 setae, and article 5 slightly shorter and narrower than 4, with 3 simple distal setae. 2 coupling hooks medially on endite. Endite distally reaching to mid of third palpal article, with 1 fan­like seta.

Pereopods ( Figs. 18­19 View FIGURE 18 View FIGURE 19 ) similar in shape; P 1 shortest, posterior pereopods longer than anterior. P 1 ( Fig. 18 View FIGURE 18 ) of female with few setae. Basis longest article, with 5 setae; ischium with 1 ventral and 2 dorsal setae; merus with 2 ventral, 1 lateral, and 2 dorsal setae distally; carpus 0.6 basis length, with 2 ventral setae of different lengths and 1 ventral sensory seta, one dorsal seta, propodus slightly shorter than carpus, distally slightly narrowing, with 4 simple distal setae and 1 distoventral sensory seta; dactylus with 2 distal claws, dorsal one more than twice as long as ventral and 2 long slightly fringed medial setae as well as another 4 setae distolaterally on article.

P 1 ­ 7 ( Figs. 18­20 View FIGURE 18 View FIGURE 19 View FIGURE 20 ) bases longest article, with 5­7 simple and 3­6 dorsal feather­like setae of varying lengths. Ischium of all pereopods with 0­4 dorsal setae and 1­3 ventral setae; merus shorter (0.8) than ischium, with 1­2 distodorsal setae and 1­3 ventral setae; carpus slightly shorter than propodus in P 2­4, in P 5­7 about as long as propodus, with 2­3 ventral sensory setae in P 2­4, and simple ventral setae in P 5­7, distodorsally of carpus and propodus 1 feather­like seta; propodus similar to carpus, but fewer setae. P 5 with a long and slender sensory proximodorsal seta; dactylus shortest article, 0.3 as long as propodus, with 2 claws of different lengths, 4 distodorsal setae and 2 setae inserted between claws.

Plp 2 of female ( Fig. 19 View FIGURE 19 ) operculiform, long ovate, with few lateral short and longer caudal setae.

Plp 3 exopod ( Fig. 19 View FIGURE 19 ) round oval, laterally and medially surrounded by small setules, distally bearing 1 apical long seta. Endopod twice as long as exopod, with 3 fringed long setae.

Plp 4 ( Fig. 19 View FIGURE 19 ) with bare, broad­oval endopod. Exopod slightly shorter than endopod and slender (a fourth as wide as endopod), laterally with some short setules and distally with a long fringed seta.

Plp 5 ( Fig. 19 View FIGURE 19 ) only one small oval lobe without setation.

Uropod ( Fig. 20 View FIGURE 20 ) long with quadrangular sympod which is about as long as exopod, bearing a laterodistal protrusion and 1 long seta; exopod half as long as endopod, with 2 long setae, endopod slightly broader than exopod, with 7 feather­like setae of different lengths and 2 setae.

Differences in paratype male ( Figs. 21­22 View FIGURE 21 View FIGURE 22 ):

General habitus very similar, but pereonite 1 slightly longer and 7 shorter, laterocaudal notches of pleotelson less rounded than in female ( Fig. 21 View FIGURE 21 ).

A 1 ( Fig. 21 View FIGURE 21 ), first peduncular article shorter than in female, second article only with 3 feather­like setae, first flagellar article with only 1 feather­like seta.

A 2 ( Fig. 21 View FIGURE 21 ) broken off in this male, but third article with a stronger and shorter spine in male than in female.

Mandibles ( Fig. 21 View FIGURE 21 ) very similar, in left mandibular incisor with more teeth in male, right mandibular incisor very similar in both sexes.

No differences could be observed in the male maxillula, maxilla and maxilliped.

Pereopods ( Fig. 21­22 View FIGURE 21 View FIGURE 22 ) of male ( Fig. 21 View FIGURE 21 ) with slightly fewer setae. P 1 basis with 1 distodorsal feather­like seta. P 2 with only 1 feather­like seta on basis, otherwise very similar. P 3 and 5 were broken off in male. P 4 also with only 1 feather­like seta dorsally on basis, distodorsal feather­like seta of propodus missing in male. P 6 with at least 3 long and slender setae dorsally on propodus (which is broken off in male), in female there is only 1 long distal one. P 7 of male similar, but bearing less setae and distoventrally of propodus 3 comb­like structures.

Plp 1 ( Fig. 22 View FIGURE 22 ) long and slender, damaged proximally, at least 5 times as long as distal width, tips rounded in ventral view. Pleopod 2 ( Fig. 22 View FIGURE 22 ) sympod length 2.4 width. Lateral margin slightly rounded with 3 distolateral plumose setae. Endopod inserting at 0.4 sympod length from distal tip. Stylet two thirds as long as sympod, only slightly bent. Exopod, rounded, small, bare, with distal tuft of fine setae. Plp 3 ( Fig. 22 View FIGURE 22 ) very similar to that of female, but endopod more rounded in male.

Remarks

Nannoniscus Sars, 1870   is most probably a paraphyletic genus which needs to be revised in the future. Most species of Nannoniscus   do not have antennal spines, like Nannoniscus bidens Vanhöffen, 1914 ( Brandt, 1992)   and can therefore easily be differentiated from the new species. The most similar species which also bears a long antennal spine is N. intermedius Siebenaller & Hessler, 1981   . The long spine of N. intermedius   , however, is inserted medially on the second antennal article, and not laterally on the third as in N. antennaspinis   . Moreover, the first pereonite of N. antennaspinis   is very short and not as much frontally directed as in N. intermedius   . The caudolateral spines on pleotelson of N. intermedius   are missing in N. antennaspinis   .

ZMH

Zoologisches Museum Hamburg

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Isopoda

Family

Nannoniscidae

Genus

Nannoniscus

Loc

Nannoniscus antennaspinis

Brandt, Angelika 2002
2002
Loc

Nannoniscus bidens Vanhöffen, 1914 ( Brandt, 1992 )

Vanhoffen, 1914 (Brandt 1992
1992
Loc

N. intermedius

Siebenaller & Hessler 1981
1981
Loc

Nannoniscus

Sars 1870
1870