Austrodecus taylorae

Staples, David A., 2019, Pycnogonids (Arthropoda, Pycnogonida) from the Southwest Indian Ridge, Zootaxa 4567 (3), pp. 401-449: 420-422

publication ID

https://doi.org/10.11646/zootaxa.4567.3.1

publication LSID

lsid:zoobank.org:pub:0AEFAF80-B001-4A18-88AC-5B6A189F6DCD

persistent identifier

http://treatment.plazi.org/id/03895C33-2902-4F12-FF01-FD61FD55FD0D

treatment provided by

Plazi

scientific name

Austrodecus taylorae
status

sp. nov.

Austrodecus taylorae  sp. nov.

Figure 11View FIGURE 11 A–I; Plates 3HView PLATE 3; 4AView PLATE 4

Material examined. Holotype, male ( NHMUK 2018.24View Materials), Southwest Indian Ocean, Atlantis Bank  , 32° 42.86´S, 57° 16.34´E, ROV, 750 m, specimen JC066-4213C, stn 8.29, mooring site, on net containing Mango wood, 14 December 2011.GoogleMaps 

Paratype. One male ( NHMUK 2018.25View Materials), same collection details as for holotype. Two males ( NHMUK 2018.26View Materials), Southwest Indian Ocean, Atlantis Bank  , 32° 42.86´S, 57° 16.34´E, ROV, 750 m, specimen JC066- 4214C, stn 8.29, mooring site, on net containing Mango wood, 14 December 2011GoogleMaps  .

Description. Male holotype. Trunk ( Fig.11A, BView FIGURE 11. Plates 3HView PLATE 3, 4BView PLATE 4) papillose, quite transparent, segments 1 to 4 with dorsomedian tubercles, height each little more than half depth of trunk, those on segments 2 and 4 slightly shorter than those on segments 1 and 3, margins of tubercles uneven; lateral processes smooth, separated by about half basal width, diverging distally. Ocular tubercle tall, height almost equal to 60% of trunk length, inclined forward, over-reaching base of proboscis, tapering from broad base to narrow truncate tip, surface of basal part coarsely rugose; four eyes, unpigmented.

Proboscis 30% longer than trunk, typical of genus, down-curved, annulated distally, basal part inflated, smooth, jaws vertically bilateral.

Abdomen ( Fig. 11CView FIGURE 11) unarticulated at base, surface coarsely rugose, length about 35% of trunk length, carried horizontally, tapering slightly distally.

Chelifores absent.

Palp ( Fig. 11EView FIGURE 11) five-segmented, attached to lateral extension of cephalon, segment 1 longest segment, with 1 or 2 strong inward-facing curved spines, segment 3 next longest, greater than half length segment 1, with six inwardfacing curved spines of similar shape and size.

Oviger ( Fig. 11FView FIGURE 11) four-segmented, attached to ventral extension of cephalon, second segment with strong recurved spine on distal margin, segment 4 longest, constricted at tip and accompanied by several spines.

Third leg: ( Fig. 11DView FIGURE 11) femur widest and longest segment, single mid-ventral femoral cement gland duct legs 3 and 4 only, conical, height little more than one-third width of femur, tibia 1 longer than tibia 2, tibia 2 more setose ventrally than other segments, femur with single long dorsodistal hair-like spine on low process, first coxae with prominent dorsodistal digitiform tubercles in the order of 1:2:2:1, coxa 2 longer that coxae 1 or 3, third coxa with a distinctly bifurcate tubercle about one-third the height of those on coxa 1 ( Fig. 11IView FIGURE 11), tarsus short, with several median spines and two longer dorsolateral spines, propodus gently curved, heel absent, sole lined with about ten short spines, without major heel spines, terminal claw about 40 percent of propodus length, auxiliary claws almost half length main claw, flared outward. Gonopores not evident.

Measurements of holotype (mm). Trunk length (frontal margin of cephalic segment to tip of 4 th lateral process), 0.784; width across 2 nd lateral processes, 0.400; proboscis length (dorsal), 1.016; abdomen length (lateral), 0.280; height ocular tubercle (lateral), 0.456. Third leg: coxa 1, 0.120; coxa 2, 0.128; coxa 3, 0.088; femur, 0.480; tibia 1, 0.440; tibia 2, 0.368; tarsus, 0.048; propodus, 0.280; claw, 0.112; auxiliary claws, 0.048. Palp: seg. 1, 0.576; seg 2, 0.080; seg. 3, 0.304; seg. 4, 0.040; seg. 5, 0.032. Oviger: seg. 1, 0.032; seg. 2, 0.040; seg. 3, 0.032; seg. 4, 0.088.

Etymology. Named for Dr Michelle Taylor, whose drive, direction and organization of all biological aspects contributed significantly to the efficient operation of the voyage.

Remarks. The basal part of ocular tubercle surface is particularly rugose with tiny pyramid-shaped projections. There is variability in the shape of oviger segment 4 which may be age dependent. In the holotype there is a strong constriction near the tip accompanied by one or two small spines ( Fig. 11FView FIGURE 11) whereas oviger segment 4 of one paratype is without apparent constriction ( Fig. 11GView FIGURE 11) but spination is similar. The fourth oviger segment of one smaller (less mature?) male is shorter, slightly ovate and without distal constriction ( Fig. 11HView FIGURE 11).

Austrodecus taylorae  sp. nov. is one of seven species in which males possess cement glands on legs 3 and 4 only. The other species are A. acone Hedgpeth and McCain, 1971  , A. bathyale Stock, 1991  , A. excelcum Stock, 1991  , Austrodecus  sp. C (below), A. latum Stock, 1991  and A. tuberculatum Stock, 1991  . The cement gland in all these species except A. acone  opens through a long tube on the posterior surface on the distal end of the femur; in A. acone  the gland opens through a basal cone with apical tube on the ventral surface of the femur. Austrodecus taylorae  and the unnamed species ‘C’ described herein are the only species in which the cement gland opens through a ventral cone lacking an apical tube. Three species are known from female specimens only and accordingly the shape, number and position of the cement glands are unknown. These species are A. elegans Stock, 1957  , A. frigorifugum Stock, 1954  and A. macrum Child, 1994b  . Austrodecus elegans  differs primarily from the new species in having very low mid-dorsal tubercles and tiny auxiliary claws. Austrodecus frigorifugum  differs in possessing very tall tubercles on the mid-dorsal surface of the trunk, no auxiliary claws and a very much shorter proboscis. Austrodecus macrum  is a far more elongate species with mid-dorsal tubercles low to absent. Cement gland ducts have also not been recorded in A. varum Child, 1994b  and A. palauense Child, 1983  however the descriptions of both species were based on juveniles. Austrodecus varum  is distinguished from the new species by low or non-existent mid-dorsal tubercles and an exceptionally long dorsodistal process on coxa 1. Austrodecus palauense  can be distinguished from A. taylorae  by more widely spaced lateral processes and the absence of auxiliary claws.

Compared to A. bamberi  , A. taylorae  is more compact and differs most noticeably in the shorter ocular tubercle and in the lesser number of femoral cement glands.

Kingdom

Animalia

Phylum

Arthropoda

Class

Pycnogonida

Order

Pantopoda

Family

Austrodecidae

Genus

Austrodecus

Loc

Austrodecus taylorae

Staples, David A. 2019

2019
Loc

Austrodecus taylorae

Staples 2019

2019
Loc

Austrodecus taylorae

Staples 2019

2019
Loc

A. taylorae

Staples 2019

2019
Loc

A. taylorae

Staples 2019

2019
Loc

A. macrum

Child 1994

1994
Loc

Austrodecus macrum

Child 1994

1994
Loc

A. varum

Child 1994

1994
Loc

Austrodecus varum

Child 1994

1994
Loc

A. bathyale

Stock 1991

1991
Loc

A. excelcum

Stock 1991

1991
Loc

A. latum

Stock 1991

1991
Loc

A. tuberculatum

Stock 1991

1991
Loc

A. palauense

Child 1983

1983
Loc

Austrodecus palauense

Child 1983

1983
Loc

A. acone

Hedgpeth and McCain 1971

1971
Loc

A. acone

Hedgpeth and McCain 1971

1971
Loc

A. acone

Hedgpeth and McCain 1971

1971
Loc

A. elegans

Stock 1957

1957
Loc

Austrodecus elegans

Stock 1957

1957
Loc

A. frigorifugum

Stock 1954

1954
Loc

Austrodecus frigorifugum

Stock 1954

1954
Loc

Austrodecus

Hodgson 1907

1907