Brevisomabathynella leijsi, Cho & Humphreys, 2010
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publication ID |
https://doi.org/ 10.1080/00222930903537066 |
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persistent identifier |
https://treatment.plazi.org/id/03D887F9-FFC7-FFCA-FE32-FF06B3196A12 |
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treatment provided by |
Carolina |
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scientific name |
Brevisomabathynella leijsi |
| status |
sp. nov. |
Brevisomabathynella leijsi sp. nov.
( Figures 30–33 View Figure 30 View Figure 31 View Figure 32 View Figure 33 )
Material examined
Holotype (adult male), allotype (adult female), paratype (six adult males and four adult females). Holotype: dissected on five slides ( WAM C 40300) . Allotype: dissected on five slides ( WAM C 40301) . Paratypes: one male dissected on five slides ( WAM C 40302) , five males and four females each as a whole specimen in a slide ( WAM C 40303–C 40311) .
Type locality
Australia, Western Australia, Nabberu Palaeodrainage, Cunyu Station , SBF calcrete, MEB site 36 (25°46′51″ S, 120°06′27″ E), BES 12859, 6 April 2005, leg. W.F. Humphreys and R. Leijs GoogleMaps .
Description of adult male (holotype)
Body. Length 1.72 mm. Head as long as anterior three thoracic segments 1–3 combined, approximately 11 times as long as wide ( Figure 30A View Figure 30 ).
Antennule ( Figure 30B View Figure 30 ). Seven-segmented. First segment with one seta on inner margin, with two simple dorsal setae and with one dorsal, one ventromedial and two lateral plumose setae. Second segment with one group of four plumose setae and with four simple setae on inner margin. Third segment with three lateral setae including one plumose seta and three setae on inner margin. Inner flagellum of third segment with three simple setae. Fourth segment with one stub seta and one plumose seta on dorsal margin, and with two stub setae and two plumose setae on outer distal apophysis. Fifth segment with three setae on inner margin and one simple seta and one aesthetasc. Sixth segment with four setae on inner margin and with dorsal group of two aesthetascs, one simple seta and one additional aesthetasc lateral to simple seta. Middle part of aesthetascs barely reaching seventh segment. Seventh segment with three subterminal aesthetascs and four simple setae.
Antenna ( Figure 30C View Figure 30 ). Five-segmented, as long as antennular segments 1–4 combined. Fourth segment shorter than fifth segment. Setal formula: 0+0/0+0/1+1/1+1/ 3(1). Plumose seta of distal segment shorter than longest simple seta.
Labrum ( Figure 30D View Figure 30 ). Flat with 10 median teeth of more or less similar size flanked by two (left) or three (right) smaller teeth on each side. Ventral surface with numerous combs of ctenidia and four teats.
Mandible ( Figure 30E View Figure 30 ). Incisor process of five teeth. Tooth of ventral edge triangular. Spine row consisting of eight spines. Palp of one segment, with one apical seta.
Maxillule ( Figure 30F View Figure 30 ). Two-segmented. Proximal segment with four setae on inner margin. Distal segment with two terminal spines, with five spines with denticles on inner edge, and with three simple setae on outer margin. Proximal spine on inner edge tiny.
Maxilla ( Figure 30G View Figure 30 ). Four-segmented, setal formula 4-5-14-8.
Thoracopods I–VII ( Figures 32 View Figure 32 A–D, 33A–C). Thoracopods I–IV increasing in size posteriorly. Thoracopods IV–VII similar in size. Thoracopods II–VII each bearing
one epipod on protopod. Basipod of thoracopods I–VII with one seta. Number of exopodal segments of thoracopods I–VII: 4-5-5-5-5-5-4. Endopod of thoracopods I–VII four-segmented, setal formulae:
Th. I 3+1/3+1/1+1/4(2)
Th. II–V 1+1/3+1/0+1/4(2)
Th. VI 1+1/2+1/0+1/3(1)
Th. VII 1+1/1+1/0+1/3(1)
Thoracopod VIII ( Figure 31A,B View Figure 31 ). Rectangular in frontal view, 1.7 times as long as wide. Protopod massive, with prominent penial region with terminal opening. Epipod large, triangular, distal part reaching penial region of protopod. Basipod without setae, inner margin of basipod projected. Exopod one-third size of basipod, triangular, terminally with five denticles, bearing two subterminal setae. Endopod half as long as exopod, with two terminal setae.
First pleopod. Absent. Uropod ( Figure 31E,F View Figure 31 ). Fourteen spines of similar size on inner margin of sympod. Exopod 63% as long as sympod, with eight setae on outer and terminal margin, without basiventral setae. Endopod 51% as long as sympod, with two dorsal plumose setae near base, with two terminal setae and one subterminal plumose seta on outer margin, and with one terminal, one subterminal and three additional spines on inner margin. Terminal spine longer than subterminal spine. Inner-marginal spine spikelike, half as long as subterminal spine.
Pleotelson ( Figure 31E,G View Figure 31 ). One seta near base of each fucal ramus on both sides. Anal operculum concave.
Furcal rami ( Figure 31E,G View Figure 31 ). Twice as long as wide, with two large terminal spines, six additional spines on inner margin, and with two dorsal setae.
Description of adult female (allotype)
Body. Length 1.67 mm. Identical to male except for following characters.
Antennule. Fifth segment with four setae on inner margin.
Thoracopods IV, V. Setal formulae of endopods:
Th. IV 1+1/2+1/0+1/4(2)
Th. V 1+1/2+1/0+1/4(2)
Thoracopod VIII ( Figure 31C View Figure 31 ). Conical, half as long as endopod of male thoracopod VIII.
Intraspecific variation
Range of body length of paratypes: 1.31–1.70 mm. Variation in number of setae, spines or segments of extremities as listed in Table 7.
Etymology
The specific name refers to one of the collector (Dr. R. Leijs: Adelaide, Australia).
| WAM |
Western Australian Museum |
| R |
Departamento de Geologia, Universidad de Chile |
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