Armadillidae (Crustacea: Isopoda) from Lord Howe Island: New Taxa and Biogeography
Lillemets, B.
Wilson, G.
Records of the Australian Museum
2002
54
71
98
4QTDN
Lillemets & Wilson, 2002
Lillemets & Wilson
2002
[942,1210,982,1006]
Malacostraca
Armadillidae
Pyrgoniscus
Animalia
Isopoda
15
86
Arthropoda
species
scopelicus
sp. nov.
Figs. 12–14
Type material. HOLOTYPEƋ, P59946, 10.7 × 6.0 mm, Ball’s Pyramid K&M 24.i.80. PARATYPES, all from Ball’s Pyramid, K&M 21.i.80 or 24.i.80: P59950, 14.2 × 8.6 mm.; P59997, Ƌ, 5 SEM stubs; P59947, Ƌ; P59949, Ƌ; P59998, ♀, 3 SEM stubs, photo K.1037; P59951, 2 ♀♀; P59948, 3 ♀♀. Typelocality. Ball’s Pyramid(near Lord Howe Island), New South Wales, Australia, 31°46'S 159°16'E, collected under and behind exfoliating rock, crevice in rock face, K&M, 21& 24 January 1980. Additional material. P34877, 9 inds; P34878, 27 inds; Ball’s Pyramid, collected under and behind exfoliating rock, crevice in rock face, K&M, 24.i.80.
Diagnosis. Cephalonfrontal lamina entire, straight; ridgelike tubercle above each eye. Pereonite1 dorsal ornamentation with midline tubercles forming a “V” behind anterior margin, area around it smooth, tubercles concentrated in two round “shoulder” areas. Pleonitesdorsal surface smooth. Pleotelsonhourglass shape; posterior margin straight; single midline ridge distally from level of constriction, not reaching posterior margin. Male pereopod1 carpus distoventrally with “brush” of setae, increasing in length distally. Uropodprotopod length 1.9 width; dorsal surface ridged; endopod 3.0 exopod length.
Description. Colouruniform grey-brown in alcohol. Body( Fig. 12A,B,G) dorsoventrally flattened with expanded horizontal epimera. Cephalon( Fig. 12C,D) frontal lamina raised above vertex, uncleft, straight, distal lateral margins triangular; ridge-like tubercle above each eye, row of low, Figure 12. Pyrgoniscus scopelicus n.sp.A–C, paratype ♀ (P59998); A,B, light micrographs, A, dorsal view, B, lateral view; C, head and pereonite 1, dorsal view. D–F,H,I, paratype Ƌ (P59997); D, head, ventral view; E, epimera 1–2 endolobes; F, pleon and pereonite 7, dorsal view; G, holotype Ƌ (P59946), light micrograph, lateral view; H,I, pleotelson and uropods, H, ventral view, I, dorsal view. Scale bar = 1 mm. Figure 13. Pyrgoniscus scopelicus n.sp.Paratype Ƌ (P59949); A, pleopod 1, ventral view, and tip, dorsal view; B, pleopod 2 and exopod tip, ventral view. Scale bar = 1 mm. rounded tubercles along posterior margin, scattered low rounded tubercles; head width 2.5–3.0 length. Eyes with 17–20 ocelli in adults. Pereon( Fig. 12A–C) epimera 1 narrowly rounded anteriorly, lateral margin simple, posterior margin rounded rectangular, dorsal surface concave, ventral surface with longitudinal ridge close to tergite epimera junction extending from anterior margin, ending in toothlike endolobe anterior to posterior margin; epimera 2 anterior margin rectangular, posterior margin rounded rectangular, ventral surface anterior margin thickened, extending in blunt tooth-like endolobe close to tergite junction near midline; epimera 3–7 anterior margins rectangular, decreasingly angled towards posterior, epimera 7 straight; epimera 2–4 posterior margins rounded, that of epimera 5–7 rectangular; epimera 3–7 endolobes absent. Tergites1–6 posterior margins slightly curved, tergite 7 straight; tergite 1 length 0.25 pereon length. Dorsal ornamentation( Fig. 12A–C) tergite 1 midline tubercles forming a “V” behind anterior margin, area around it smooth, tubercles concentrated in two round “shoulder” areas, rest of tergite with scattered tubercles, narrow band along posterior margin smooth; tergite 2–7 each with row of tubercles, smooth narrow band along posterior margin; epimera 1 with scattered tubercles, epimera 2–7 ridged; tergal cuticle with small scattered scales. Pleon( Fig. 12F) pleura 3–5 truncate, ridged; pleonite 1–2 posterior margin straight, pleonite 3–5 slightly curved; endolobes absent; pleonites dorsal surface smooth. Pleotelson( Fig. 12I) hourglass shape, greater part posterior to constriction, proximal width 0.9 distal width, length 0.9 proximal width; posterior margin straight; two rounded tubercles near anterior margin, midline ridge distally from level of constriction, not reaching posterior margin. Antenna( Figs. 12C,D, 14L) long, slender, reaching epimera 2 posterior margin; flagellum length 0.6 article 5 length; flagellar articles length proportions 1:2; all segments setose, flagellum with long apical seta. Mandibles( Fig. 14 A,B,D,E). Right mandible lacinia mobilis base setose lobe with row of long simple setae; left mandible with 6 robust penicils. Maxilliped( Fig. 14F,G) palp article 2 apical group of setae on small lobe. Male pereopod1 ( Fig. 14H,I) carpus distoventrally with “brush” of setae, increasing in length distally. Penes( Fig. 14K) lanceolate; proximal bilobed lamellar process triangular, length 0.4 penes length. Male pleopod1 ( Fig. 13A,B) exopod triangular, with four separate lateral setae near apex; pseudotrachea along proximal lateral margin, width 0.5 exopod width, length 0.5 exopod length; exopod length 0.35 endopod length. Pleopod 2 exopod length 2.0 width, proximal wide portion length 0.3 exopod length, pseudotrachea along lateral margin, width 0.5 exopod width, length 0.2 exopod length, distolateral row of long, thick setae; endopod proximal article length 0.2 endopod length; exopod length 0.75 endopod length. Pleopods 3–5 exopods ridged near dorsolateral margin, ventral long thick setae along lateral margin of apical half. Uropod( Fig. 12H,I) protopod length 1.9 width; proximal medial margin straight portion 0.2 protopod length; protopod distally visible dorsally, length 0.67 protopod length; length (along inner margin of dorsally visible portion) 2.0 width (at point of exopod insertion); dorsal surface ridged; exopod inserted dorsally midway to apex, length 0.25 protopod dorsally visible portion length; endopod 3.0 exopod length.
Etymology. Scopelicusmeans “of a rocky crag projecting from the sea”, a good description of Ball’s Pyramid.
Remarks. We here list all species that have been recorded in Pyrgoniscusand indicate how P. scopelicus n.sp.differs from them. The frontal lamina is lower in P. scopelicusthan in P. lanceolatus Ferrara, 1977and P. petiti Monod, 1935. The straight frontal lamina differentiates it from P. intermedius Lewis, 1998b(also from Lord Howe Island). Unlike this species, the frontal lamina is cleft in P. cinctutus Verhoeff, 1926, P. exilis( Budde-Lund, 1885), P. translucidus translucidus( Budde-Lund, 1885), P. hispida( Vandel, 1973), P. canaliculatus( Budde-Lund, 1904), P. iniquus( Budde-Lund, 1904), P. noduligerus( Verhoeff, 1926), P. translucidus gracilio( Verhoeff, 1926), P. bicarinatus( Budde-Lund, 1913)and P. chathamensis( Budde-Lund, 1885). Pyrgoniscus carinatus( Verhoeff, 1926)has a straight sided pleotelson rather than an hourglass shape. A single ridge on the pleotelson separates this species from P. impressifrons( Budde-Lund, 1904)by a single ridge on the pleotelson, and from P. rugosus( Budde-Lund, 1913)by differences in dorsal ornamentation (see Fig. 12A,B).
P59946
Ball's Pyramid K
15
86
1
holotype
P59950
15
86
1
paratype
P59997
[1137,1384,1145,1168]
15
86
1
paratype
P59947
15
86
1
paratype
P59949
[1043,1162,1174,1198]
15
86
1
paratype
P59998
[1175,1330,1174,1198]
15
86
1
1
paratype
P59951, P59948
15
86
5
5
paratype
1980-01-24
Australia
-31.766666
Ball's Pyramid
1214
159.26666
Lord Howe Island
15
86
1
New South Wales
holotype