23,316 research outputs found
Parartemia purpurea Timms, 2010, sp. nov.
No full textParartemia purpurea sp. nov. (Figs 4,7,11) Parartemia n sp a Timms and Savage, 2004, p 22, 28; Timms 2009. Etymology. This species is named for the distinct purple colouration of mature females, the name being derived from the Latin purpurea meaning purple. Holotype. One male, 44 km NNE of Esperance, unnamed lake on Dempster Rd, (33 o 28 ’ 58 ”S, 122 o 00’ 38 ”E), 8 October 2008; BVT, WAM 45235. Allotype. One female, same collecting data as holotype, WAM 45236. Paratypes. Two males, two females, some collecting data as holotype, WAM 45237; two males, two females, same collecting data as holotype, AM 82976. Other material. 10 males, 10 females, 23.5 km E of Scaddan, unnamed lake on East Lignite Rd, (33 o 19 ’ 28 ”S, 121 o 58 ’ 17 ”E), 2 August 2005, BVT, WAM 45238; 10 females, 38 km N of Esperance, unnamed lake on south side of Speddingup Rd, (33 o 31 ’ 01”S, 121 o 52 ’ 21 ”E), 8 October 2008, BVT, WAM 45239; 10 males, 10 females, all immature, 64.5 km NE of Esperance near Kau Rock, unnamed pond, (33 o 24 ’ 32 ”S, 122 o 20 ’ 00”E), 9 October 2008, BVT, WAM 45240; 10 males, 10 females, 80 km NE of Esperance in Beaumont Nature Reserve, unnamed lake, (33 o 27 ’ 37 ”S, 122 o 36 ’ 43 ”E), 5 September 2004, BVT, WAM 45241. Description. Male. Length 21.5 mm (head plus thorax 7 mm, abdomen 14.5 mm) First antenna (Fig. 11 A) filiform, a little longer than eye plus peduncle. Second antenna. Basal antennomeres (Fig. 11 A) fused at about 75 o to body axis. Ventral margin with paired ventral processes (Fig. 11 A) about 3 times longer than deep, with distoventral corner rounded but not protruding and medioventral corner sharp, almost a right angle. Ventral process margin with well spaced minute spines, also a few such spines on dorsal surface of the processes. Medial margin of ventral processes about 1.2 times longer than lateral margin. Medial space between ventral processes narrow with parallel margins and terminating basally in a short notch. Ventrolaterally just lateral to basodistal margin of the ventral process a raised circular area, the conical mound, with numerous minute spines. Anterior processes (Fig. 11 A) small, blunt triangular, about one quarter depth of ventral processes. Distal antennomere (Fig. 11 A) almost twice as long as basal antennomere, curved medially, cylindrical and tapering to a sharp apex. Labrum lacking a spine. Thoracomeres (Fig 10 B) enveloped laterally in small fused lobes to form a narrow lateral flange along whole length of thorax. Thorax widest at thoracomeres 10 to 11, with lobe on first genital as wide as lobe on T 11 anteriorly, but markedly narrowing posteriorly. No lobe on second genital segment. Eleven pairs of thoracopods, with first two reduced in size and last without an epipodite. Fifth thoracopod typical for the genus. Gonopods (Fig. 11 C) fused basally. Each apical free portion with a short hooked digitiform process inserted ventrolaterally at about three quarters the length of the free portion. No basal spine. A paratype with gonopod everted (Fig. 11 D)— everted part a little longer than free basal portion, consisting of a basal wide cylindrical component and a tubular distal part of two diameters, a middle section narrower than basal tube and an apical, very narrow apical section. Whole expanded section naked except for a two recurved spines on a single base posteriolaterally on the wide cylindrical component. Abdomen long, 2.1 times head plus thorax. Segments increasing in length and but hardy decreasing in diameter sequentially 1 to 6, with sixth 2.2 times the length and but only marginally narrower than first segment. Telson inflated and not clearly demarked from sixth abdominal segment and cercopods about length of fourth abdominal segment and clothed with setae medially and laterally. Female. 11 mm (head plus thorax 6.7 mm, abdomen 4.3 mm). In life, mature females coloured a deep purple, with the brood chambers a lesser intense colour. Head (Fig. 11 E) with first antenna filiform and slightly shorter than length of eye plus peduncle. Second antenna a little longer than twice eye plus peduncle length, somewhat flattened, and narrowing evenly to a sharp apex. Labrum with a prominent recurved spine. Thoracomeres (Fig. 11 F,G) 1 – 6 and 8 normal, thoracomere 7 with a lateral tumidity, thoracomeres 9 and 10 each with a dorsolateral lamella, with a sclerotized and denticulate margin. Dorsolateral lamella of thoracomere 9 asymmetrical, narrow dorsally and widest ventrolaterally and with subsidiary ventrolateral lamella, while lamella of segment 10 more symmetrical and more ventrolateral. Thoracomere 11 somewhat reduced. Eleven pairs of thoracopods, 2 nd and 10 th pairs a little shorter than most, 1 st about half size and 11 th reduced to just a pair of stubs bearing a few spines. First thoracopod (Fig. 7 J) with all normal components, but endopod and particularly exopod reduced, so that both have fewer posterior seate than normal and exopod just protruding beyond endopod. Normal anterior setae, and with basal anterior setae of endite 4 enlarged, longer than adjacent posterior setae. Fifth thoracopod of normal construction for Parartemia and similar to that in males. Tenth thoracopod (Fig. 7 K) with most structures reduced, particularly endites 1 + 2 and 3, endopod and praeepipodite, and with epipodite lacking. Exopodite of normal relative size and projecting well beyond the endopodite. Anterior setae of endites all present, but reduced in size. Eleventh thoracopod (Fig. 7 L) a stub with terminally what appears to be a very reduced endopod with five setae, and medially two protuberances, the distal one with two setae and a basal greater naked protuberance. These protuberances could be endites. Brood pouch (Fig. 11 F,G) lateral lobes oval structures in dorsal view but more quadrahedral laterally, and connected ventrally, with a posteriorly directed gonopore, borne on a tubular projection. Abdomen segments typical for Parartemia, i.e. segments increase in length and decrease in diameter sequentially from segments 1 to 6. Surface denticulate. Variability. Mature males vary in length from 16 to 23 mm. The basal antennomeres are fused at various angles, probably influenced by preservation, of 60–80 o to body axis and while the frontal processes seem always to be small, blunt and triangular, the ventral processes vary so that the distoventral corner may protrude a little and the medial space varies from being almost closed to being open by a distance up to about one third the depth of the ventral processes. The medial margins of the ventral processes may not always be parallel, but occasionally are V-shaped or uneven. However, the angle of near 90 o on the medioventral corner of the ventral processes varies little. The raised spinose area ventrolaterally to the basodistal margin of the ventral processes may be expressed as a conical mound or may be hardly present. The flange on the thoracic margins is generally present, but its widest part may be at thoracomere 10 or occasionally 11, i.e. more posterior than at thoracomere 8–9. Abdomen length varies from 1.25 to 2.33 times head plus thorax length (average of 1.78 in 10 specimens). This length is due in part to the relatively long 6 th segment which on average is 2.1 times length of 1 st segment. The first ratio is greater than for P. longicaudata and the second only a little less than in P. longicaudata, the species supposedly with an extraordinary long abdomen (see earlier). Mature females range in length from 9.6 to 11.2 mm, and while opaque white in preservation, in life are almost always a deep purple. The lateral tumidities on thoracomere 7 while usually prominent, are sometimes deflated and not noticeable. The lateral lamellae of thoracomere 9 and 10 vary in development, but the lamella of thoracomere 9 is always larger than that of thoracomere 10 and more dorsal in position. Differential diagnosis. P. purpurea sp. nov. males are most similar to P. zietziana due to their broadly similar ventral processes and the shape of the medial area between these processes. However P. zietziana has digitiform anterior processes compared to short conical processes in P. purpurea sp. nov. The lateral and medial margins of the ventral processes are of similar length in P. zietziana, but the medial margin is about 1.2 times longer than lateral margin in P. purpurea sp. nov. The ventrolateral area at the basodistal margin of the ventral processes is different in the two species: in P. purpurea sp. nov. it is raised and very spinous, but in P. zietziana it hardly present, if at all. Finally the abdomen is relatively longer in most specimens of P. p u r p u re a sp. nov. (1.78 times) than in P. zietziana (1.30 in 10 specimens). The two species have different distributions separated by the Nullarbor Plain – P. zietziana occurs in central lowland Tasmania, southern Victoria, and southern South Australia to as far west as the eastern Eyre Peninsula, while P.purpurea sp. nov. occurs in the Esperance hinterland area of Western Australia (Timms et al., 2009). Females are distinct from all other species due to the lack of dorsal swellings and horizontal lateral lobes on various thoracic segments, and the presence of lateral swellings on thoracomere 7 and vertical lateral flaps on thoracomere 9 and 10. Furthermore it is unusual in Parartemia females to have a vestige of thoracopod 11 as P. p u r p u re a sp. nov. does; closest species in this character is P. acidiphila with 3 terminal setae, P. laticaudata sp. nov. with two terminal spines and P. longicaudata with a subterminal spine. Distribution and ecology. P. purpurea sp. nov. occurs in alkaline saline lakes in the Esperance hinterland, from about Grass Patch-Scadden eastwards for about 90 km to Beaumont Nature Reserve (Timms et al., 2009)(Fig. 4). It occurs over a salinity range of 20 to 235 g /L and in lakes with pH varying from 6.9 to 10.4 (Timms, 2009 b; Timms et al., 2009). Generally it occurs in late winter- spring as lakes fill with winterspring rains, reproduces in September and October with purple coloured females actively swimming in the shallows and depositing eggs. Occasionally summer rains fill the lakes, in which case P. purpurea sp. nov. responds as it does to a winter filling (Timms, 2009 b). Females are easily predated upon by waders (mainly Stilts, Avocets) as they swim conspicuously in shallow waters, so that sex ratios can become very biased towards males which tend to stay in deeper waters (author, unpublished observations). Presently it is common throughout this area as few lakes are salinised.Published as part of Timms, Brian V, 2010, Six new species of the brine shrimp Parartemia Sayce 1903 (Crustacea: Anostraca: Artemiina) in Western Australia, pp. 1-35 in Zootaxa 2715 on pages 24-27, DOI: 10.5281/zenodo.19970
Branchinella herrodi Timms, 2012, sp. nov.
No full textBranchinella herrodi sp. nov. Figs. 1 G, 8, 9A. Etymology. This species is named for the Herrod family longtime proprietors of Yarromere Station, via Pentland, North Queensland, in particular patriarch Kevin Herrod for his assistance and concern for my well being as I collected shrimp in remote parts of the property. Type locality. Queensland, Lake Buchanan northwest beaches, pool 1.3 km sw of Lake Constant southern shore, 21 o 34 ’ 31 ”S, 145 o 47 ’ 32 ”E, 24 February, 2008, BVT Holotype Male deposited in Australian Museum. Total length 9.5 mm. Accession number: AM P 88354. Allotype Female deposited in Australian Museum. Total length 11.2 mm. Accession number: AM P 88353. Paratypes. Queensland, Lake Buchanan northwest beaches, pool 1.3 km NE of Lake Constant northern shore, 21 o 32 ’ 38 ”S, 145 o 48 ’ 29 ”E, 26 February, 2008, BVT, AM P88355, 4 males, 3 females. Other Material. Queensland, Lake Buchanan northwest beaches, pool 1.3 km w of Lake Buchanan northwest shore, 21 o 32 ’ 00”S, 145 o 48 ’ 13 ”E, 26 February, 2008, BVT, AM P88356, 5 males, 3 females. Diagnosis. Frontal appendage branched, each branch with ca 10 lateral subbranches and 5 lateral medial branches plus a larger one basomedially. Branches terminate in a mixture of small spines and epidermal outgrowths. Male fifth thoracopods distinct with various anterior setae and endopod lack basal knob-like extensions (as in B. wellardi) but with 6–8 spinules on their base. Females unremarkable. Description. Male. Eyes freely projecting on peduncles about the same length as eye diameter. First antennae filiform, slightly longer than second antenna proximal antennomere, and terminating in 3–5 long sensory setae. Second antennae with proximal antennomere subequal in length to distal antennomere. Proximal antennomeres well separated on each side, being fused basally at 90 o and medially with a long shallow swelling covered in very small denticles. Distal antennomeres of uniform diameter and with transverse ridges medially. Frontal appendage larger than the second antennae, consisting of short trunk and two ramified branches almost three times trunk length. Each branch with 9–10 subbranches laterally and 4–5 medially, but with one larger branch of different structure basomedially. These subbranches about the same size medially and laterally and decreasing in length towards the branch apex. Each branch terminating in a short spine apically attended by 2–4 smaller spines subapically. Narrow conical outgrowths randomly distributed ventrally along each branch, mainly posteriorly to the larger medial subbranch. Similar outgrowths but smaller along the subbranch generally in pairs. Largest medial branches smooth, each consisting of a short thick trunk and an oval plate at about 60 o to the trunk, so overall the axis of the plate and branch trunk similar. Fifth thoracopod with endite 1 + 2 and 3 evenly curved, the former about three times the size of the later. Anterior setae of endite 1 smooth, and about half the length of adjacent posterior setae. Anterior setae of endite 2 about half the length of anterior seta and bearing a strong pecten of spines and attended at its base by a small smooth spine. Endite 3 with an anterior setae similar on length to the first anterior seta, and bearing a strong pecten of spines and attended at its base by a short smooth spine. Endites 4–6 asymmetrical and covered with small spines. Endites 4 and 5 with two anterior setae and endite 6 with one anterior seta, representing two types. The first on all three endites with a fine pecten most of their length and a few spines basally; the seta on endites 6 a little longer than the other two. The second seta type on endites 4 and 5 only, comparatively short (half length of adjacent anterior seta) and naked. Posterior setae of all endites long and numbering about 60 on endites 1 + 2, near 18 endite 3, then 3,2, 2 respectively on endites 4–6. Endopod squarish with a shallow wide notch apically. It bears 10 spaced feathered setae medially to the notch and 18 closer together apically and laterally. Setae larger on the apex than proximal sides. The ca 40 feathered setae on the exopod each about 50 % longer than endopod setae. Basal attachment of endopod setae with 6–8 spinules compared with 3–4 on the exopod setae base. Epipod broadly oval and naked. Praeepipodite large (about equivalent to exopod + endopod) and with smooth edges. Genital segments about same width as nearby thoracic and abdominal segments. Bases of gonopods about half the length of the first abdominal segment. No specimens with gonopod everted. Cercopods typical for Branchinella. Female. Eye plus peduncle on each side about head width. First antenna filiform, almost as eye plus peduncle. Second antenna with a wide base and narrowing to an asymmetrical sharp apex and longer than the labrum. Genital segments subequal to posterior thoracic and adjacent abdominal segments. No tumidities. Brood pouch expanded ventrally and tubular posteriorly and terminating at about the second abdominal segment. Fifth thoracopod and cercopods as in male. Egg diameter 175 µm. Depressions average number 35 and irregularly polygonal to constricted and linear, inter-depression walls wide and ridge crests rounded and with minute pores (Timms and Lindsay, 2011). Variability. There is some variability in the number of subbranches of the frontal appendage, but only one either way from the number in the holotype. The larger basomedial branch can be of various sizes, perhaps associated with the developmental stage of the specimen. As indicated for this holotype the placement of the narrow epidermal outgrowths is quite variable in other frontal appendages examined, but always they are ventral and lateral and most common in the apical half of each subbranch. Differential diagnosis. Branchinella herrodi sp. nov. is most similar to B. multidigitata Timms 2008, B. campbelli Timms 2001 and B. wellardi. Branchinella multidigitata has frontal appendage branches with subbranches reminiscent of those in B. herrodi sp. nov., but with 6 laterals, 3 terminals, 3–5 very small medials and no larger basomedial in B. multidigitata compared to 9–10 laterals, 0 terminals, 4–5 fully developed medials and a large basomedial subbranch in B. herrodi sp.nov. The basomedial subbranch in B. herrodi sp.nov. is similar to that in B. campbelli, but that is the only feature of resemblance. Given that there is <4 % variation in 16 SmtDNA (Pinceel et al., 2012) between B. herrodi sp.nov. and B. wellardi, this is the species it is most likely similar too, or indeed conspecific. While their frontal appendages are superficially similar, there are many morphological differences between the two: (a) B. wellardi has a bilobed lamellar outgrowth between the two branches, B. herrodi sp.nov. does not (Figs. 8 A, 12 A); (b) B. wellardi has 9–10 pairs of lateral and medial subbranches to the branches, whereas B. herrodi sp.nov. has 9–10 laterals and 4–5 medials (Figs. 8 B, 12 B); (c) the branches of B. wellardi are usually pseudosegmented but not in B. herrodi sp.nov. (Figs. 8 B, 12 B); (d) the subbranches have paired thickenings each terminating in a chitinous epidermal outgrowth in B. wellardi, while in B. herrodi sp.nov. the branches are of more uniform thickness, terminate in a spine attended subapically by 2–4 smaller spines and the epidermal outgrowths are scattered (Figs. 8 B, 12 B); and (e) only B. herrodi sp.nov. has a larger basomedial branch (Fig. 8 B). The second antennae of both species are very similar, though that in B. herrodi sp.nov. has a shallow tumidity covered in minute denticles medioapically, whereas the medial surface in B. wellardi lacks denticles and spinules (Figs. 8 A, 12 A). The thoracopods are also very similar, as they are in many of the smaller species of Branchinella, but four medial endopod setae are inserted on knob-like protrusions in B. wellardi compared to 6–7 medial setae inserted normally in B. herrodi sp.nov. Their bases have 6–8 spinules whereas those in B. wellardi are smooth (Figs. 9 A, B). Resting eggs of B. herrodi sp.nov. are like the undistinctive eggs of B. affinis, B. anatinorhyncha sp. nov., etc, whereas eggs of B. wellardi have markedly concave and regular polygonal depressions (Figs. 1 G, J). Thus the conclusion is inescapable that despite the being similar molecularly (in the 16 Smt segment), B. herrodi sp.nov. is distinct from B. wellardi. Distribution and Ecology. B. herrodi sp.nov. is common in many of the clear freshwater pools in old swales between the fossil high beaches of Lake Buchanan. They have not been found in hyposaline/mesosaline pools associated with Lake Buchanan and its inflowing streams, nor in the saline lake itself (the domain of Parartemia minuta Geddes 1973 and Branchinella buchananensis Geddes 1981) (Timms, 1987), nor in claypans in the greater region. Most of the pools only contain water after heavy summer rains.Published as part of Timms, Brian V, 2012, Further studies on the fairy shrimp genus Branchinella (Crustacea: Anostraca: Thamnocephalidae) in Australia, with descriptions of five new species, pp. 35-60 in Zootaxa 3595 on pages 49-52, DOI: 10.5281/zenodo.25459
Lynceus magdaleanae TIMMS, 2013, sp. nov.
No full textL. magdaleanae sp. nov. (Figs. 3E, 4E, 12) Etymology. This species is named for Magdaleana Davis (nee Zofkova) to honour molecular her work in identifying the presence of at least three species of Lynceus in Western Australia. Type locality. Australia, Western Australia, 18 km NE of Goomalling, East Oak Park pit gnamma, 31 o 08’ 20”S, 116 o 52’ 49”E, 19 October 2011, collector BVT. Holotype. Male deposited in the Western Australian Museum (Perth). Length 5.5 mm. Registration number WAM 51624. Allotype. Female deposited in the Western Australian Museum (Perth). Length 5.0 mm. Registration number, WAM 51625. Paratypes. 8 altogether; 2 males and 2 females deposited in Australian Museum (Sydney) Registration number, AM P89077, and 2 males and two females deposited in Western Australian Museum (Perth), WAM 51626. Other Material. Northern Territory: Papunya, 4 km E, gnamma on Warumpi Hill, 23 o 15’S, 131 o 54’E), 14 May 1998, IAEB, AM P90069; Macdonnell Ranges, Palm Creek in PalmValley, 24 o 03’ 25”S, 132 o 44’ 47”E, 13 September 1958, D.F. McMichael, AM P55727 & P88376; Kata Tjuta (= Mt. Olga), 25 o 17’ 22”E, 130 o 44’ 18”E, 11 August 1966, A Frecker & P. Keane, AM P55684 & P88157. Queensland: 105 km N of Hughenden, L. Louisa, 19 o 53’ 36”S, 144 o 15’10”E, 7 April 2009, BVT & MS, AM P89078; 7 km E of Boulia, burrow pit, 22 o 54’ 44”S, 139 o 58’24”E, 4 March 2011; BVT & MS, AM P89079; 2 km E of Boulia, swamp, 22 o 54’ 41”S, 139 o 55’ 30”E, 4 March 2011, BVT & MS, AM P90067; 76 km NE of Aramac, L Galilee Hazelmere Inlet, 22 o 26’ 00”S, 145 o 42’30”E, 15 February, 2010, BVT & MS, AM P90068. South Australia: Musgrave Ranges, Erliwunyawunya Rockhole, 29 May 1961, H.G. Cogger, AM P15286, P55685, P88143, P88380; Musgrave Ranges, 7 km S of Mt. Woodroffe, waterhole in Currie Creek tributary, 9 May 1983, 26 o 19.134’E. 131 o 44.715’E, W. Zeidler, SAM C7631; Everard Ranges, Carmeena Rockhole, 27 o 06.51’S, 132 o 33.011’E, 14 August 1914, Capt S. A. White, SAM C7632; Everard Homestead, Victoria Springs, 27 o 0.368’S, 132 o 42.565’E, 31 October 1970, E Matthews SAM C7646; Gawler Ranges, pool near Hiltaba Homestead, 32 o 09.422’S, 135 o 04.084’E, P. Aerfeldt & P. Cokerham, 14 October 1984, SAM 7633; Gawler Ranges, pool near Yarna Homestead, 32 o 03.213’S, 135 o 07.751’E, P. Aerfeldt & P. Cokerham, 15 October 1984, SAM C7634; Gawler Ranges, pool near Paney Homestead, 32 o 35.240’S, 135 o 25.803’E, P. Aerfeldt & P. Cokerham, 16 October 1984, SAM C7635; Gawler Ranges National Park, 40 km NE of Wudinna, Policemans Point, 32 o 35’ 17”S, 135 o 26’ 30”E, 5 October 2009, BVT, SAM C7636; 13.5 km NE of Minnipa, Pildappa Rock, western pit gnamma, 32 o 45’ 05”S, 135 o 13’ 48”E, 23 November 2003, BVT, SAM P7637; 25 km ENE of Wudinna, Peela Rock, northernmost pit gnamma, 33 o 00’ 09”S, 135 o 43’ 28”E, 26 October 2011, BVT, SAM C7638; Frances, Lake Cadnite, 36deg 42.685’S, 140deg 56.559’E, 6 May 1979, W. Zeidler, SAM C7639. Western Australia: Little Sandy Desert, Hutton Range, 16 km N, ca 24 o 46’S, 123 o 48’E, 4 September 1971,no collector recorded, WAM 51322; 83 km N of Northhampton, Euardy Station, roadside ditch, 27 o 36’ 31”S, 114 o 41’ 43”E, 5 July 2011, Koen Martens, WAM 51591; 50 km NW of Cue, pit gnamma on Walloo Hill, 27 o 14’ 47”S, 117 o 25’ 44”E, 23 August 2009, BVT, WAM 51592; Gibson Desert, Gunbarrel Highway, Mt Samuel, pool (probably one of the Mangi gnammas) 1.6 km WSW, 1 June 1966, 25 o 45’ 50”S, 125 o 55’ 50”E (for Mt Samuel), K. Davey. AM P55668, P88159; Great Victoria Desert, Knight Gnamma Holes, 28 o 12.795’S, 124 o 39.993’S, 25 August 2010, IAEB, WAM 51593; Great Victoria Desert, Sunday Surprise Rocks, 27 o 57.379’S, 125 o 00.350’E, 27 August 2009, IAEB, WAM 51594; 60 road km SE of Giles, Kutjurritari Gnammas, ca 25 o 17’S, 127 o 49’E, 23 September 2009, BVT, WAM 51595; Great Victoria Desert, Connie Sue Highway, gnammas 10 km W of Lake Serpentine, 26 August 1980, J.A. Forrest, WAM 51596; Warburton, Windaroo Rockhole, 21 June 1979, J. Blyth, WAM 51597; 71 km WSW of Menzies, pit gnamma on Scorpion Rocks, 29 o 51’ 10”S, 120 o 19’ 36”E, 10 October 2011, Bindy Datson, WAM 51598; Paynes Find area, 2 September 1991, no date or collector recorded, WAM 51317; 11 km NNW of Paynes Find, south pit gnamma on Bullamanya Rocks, 29 o 09’ 53”S, 117 o 39’ 36”E, 5 October 2010, BVT, WAM 51599; 15 km SW of Wubin, pit gnamma on Miamoon Rocks, 30 o 09’ 07”S, 116 o 20’ 45”E, 14 September 2003, BVT, WAM 51600; 25 km E of Wongan Hills, Dingo Rock, 30 o 50’ 41”S, 116 o 58’ 30”E, 27 September 2012, BVT, WAM 51601; 43 km NNW of Hyden, rock pool at base of Mt Walker; 32 o 04’ 11”S, 118 o 45’ 21”E, 31 August 2009, BVT, WAM 51602; 17 km NE of Hyden, northern pit gnamma at The Humps, 32 o 18’ 41”S, 118 o 57’ 37”E, 4 August 2005, BVT, WAM 51603; near Buncubbin, Dajoing, soak at Yalburnunging Rock, no date, E. Simpson, WAM 51318; 40 km NE of Mukinbudin, pit gnamma on Yanneymooning Rock, 30 o 43’ 04”S, 118 o 33’ 24”E, 24 October 2010, BVT, WAM 51604; 44 km S of Coolgardie, pit gnamma on Victoria Rock, 31 o 17’ 37”S, 120 o 55’ 32”E, 14 September 2002, IAEB & BVT, WAM 51605; 40 km E of Lake King Township, pit gnamma on Lilian Stokes Rock, 33 o 04’ 06”S, 120 o 05’ 49”E, 1 September 2009, BVT, WAM 51606; 95 km SW of Norseman, near Metcalf Lake, creek crossing, permanent water under rock tunnel, 32 o 28’ 30”S, 120 o 49’E, no date or collector recorded; WAM 51323; Dundas, rockhole, ca 32 o 27’S, 121 o 46’E, no date or collector, WAM 6735; 27.5 km NE of Norseman, Buldania Rocks, western pit gnamma, 4 December 1959, D.H. Edwards, AM P55661 & P88381; 89.6 road kms E of Norseman off Eyre Highway, Smithania Rock, June 1964, Lee, AM P55656 & P88153; 196 km E of Norseman, a pit gnamma on Balladonia Rock, 32 o 27’ 41”S, 123 o 51’ 48”E, 18 March 2007, BVT, WAM 51607. Diagnosis. Thoracopod I of male with endite VI with a broad almost rectangular base because of a distinct angular hump of about 110–120 o on the distal surface, and a short somewhat triangular process medially, much shorter than the base and reaching only about a third of the medial length of endite III, and not covering all the teeth on the distomedial surface of endite III. Description of male. Head (Fig 12B,C) subequal to body size, finely punctuate. Fornices broad, angulated and arcuate over second antennal base. Small mound centroposteriorly the site of the dorsal organ. Compound eyes close together about midway along central ridge and just posterior to the frontal pore and two small lateral setal fields. Ocellus deeply embedded beneath the setal fields. Rostral dorsal surface lower than surface posterior to compound eye, the junction marked by the lateral suture from the eye to the nearby fornix. Rostrum about as long as wide with upper surface significantly expanded terminally (by about 30% each side). Central carina bold and bifurcated distally associated with terminal truncation to form a broadly based triangular terminal facet. This facet ciliated on the ventral edge and almost at right angles to head alignment and with anterior margin of base straight. First antenna (Fig 12D) small, a little shorter than rostrum, and with two antennomeres. Proximal antennomere cylindrical with concave face terminally and supporting second antennomere. This antennomere subequal in length to the first, clavate and with a few short setae terminally and on dorsal distal surface. Second antenna (Fig 12E) biramous, well developed, twice as long as rostrum. Peduncle of three segments, proximal segment with 3–4 plumose setae, middle segment with 1–2 spines and the distal peduncular segment with about 8 short spines mainly at the base of the anterior ramus. Anterior ramus with about 25 antennomeres and ventral ramus with a few more antennomeres. Both rami with long plumose ventral setae, one per antennomere, while anterior ramus with short dorsal setae also. Labrum large, well developed, clothed in small setae. Mandible broadly spatulate. First maxilla typical for genus and second maxilla absent. Carapace (Fig 12A) with hinge line slightly arcuate, umbo lacking and no growth lines. Anterior margin broadly arcuate, curving evenly to ventral margin and back to the posterior, though posterior is slightly narrower so that deepest part of carapace a little before midway along its length. Dorsally carapace slightly arcuate, thus hiding the hinge line. Valves roundly inflated laterally. Carapace surface finely punctate. Abductor muscle scar in an anteriolateral position about twice its diameter from the margin and associated with oval imprint of maxillary glands lying at about 40 o to the hinge line. Thorax. Ten thoracic segments, each with paired thoracopods. Anal plate partly divided centroposteriorly, each half bearing a long seta. Somite below enlarged, even more divided centroposteriorly and each half bearing a small denticle apically. Thoracopod I (Fig 3E, 12F) modified as a clasping appendage, the right and left claspers equal in shape and size. Endite VI with a broad almost rectangular base because of a distinct angular hump of about 110–120 o on the distal surface, and a short somewhat triangular medial process, much shorter than the base and reaching only about a third of the medial length of endite III and not covering all the spines row on the distiomedial surface of endite III. Endite V cylindrical and straight, and about two and a half times longer than broad and four to five times larger than endite IV. Endite V with a vertical row of about 13 larger stout setae from about one third of the endite’s length to its apex and also with an oval field of numerous lithe setae centred about 90 o around the palp but spreading close to the distinct setal row and covering the distal two-thirds of the palp. Endite IV oval in profile and margined with numerous setae mainly on the side distal to Endite V. Endite III rectangular but distinctly narrowing distally and with major axis at right angles to thoracopod axis. A row of about nine triangular spines distiomedially and a large field of stout setae mediolaterally clumped distally. Thoracopod II of general form for Lynceus (Martin & Belk, 1988) and depicted for L. baylyi (Fig.11) with two significant differences: 1) it lacks serrated anterior setae, all anterior setae being naked and 2) the distal lobe of the exopod narrows evenly along its length instead of having a distinctly wider area near its base. Thoracopods III to XI similar to thoracopod II, though the last three much reduced in size and lacking epipodites and proximal lobe of the exopodites. Description of female: Head (Fig. 12G,H): general structure similar to male. Compound eyes, ocellus, frontal pore and setal fields as in male. However anterior dorsal carina not bifurcated and rostrum not truncated, so that rostrum a little longer than wide. Rostrum increases in width anteriorly by about 30% on each side. Central carinae bold and lateral suture marking boundary between higher posterior surface and lower rostral dorsal surface as in male. Anterior margin of rostrum arcuate, but with a small notch at each anteriolateral corner. Carapace as in male, umbo lacking, no growth lines, same size and shape. Egg mass, if present, visible through the carapace. Thorax. Twelve thoracic segments, the last three with a lamina abdominalis laterally (Fig 12J). This lamina with an obtuse process anteriorly, two subequal triangular lateral lobes and a larger triangular lateral lobe posteriorly. A thin digital process arising dorsolaterally from a broad swollen base between the clavate process and the first triangular lobe. Anal plate as in the male, but last somite more rounded than in male. Thoracopods. 12 pairs of thoracopods, diminishing in size posteriorly, and thoracopods IX and X with exopod dorsal lobes cylindrical and extending dorsally beyond thoracic dorsum. These, plus the lamina abdominalis, help to anchor the egg mass. Resting egg. (Fig 4E) Round, irregular low wide ridges enclosing enlongated irregular depressions. Size 111.5 ± 4.6 ųm (n = 5). Size. Length holotype 5.5 mm, paratypes (n=4) 5.2 – 5.8 (x = 5.5 ± 0.35 mm); height holotype 5.0 mm, paratypes 4.2 – 5.1 (x = 4.75 ± 0.36 mm), width holotype 4.4 mm. Length allotype 5.0 mm, paratypes 4.9 – 5.4 (x = 5.15 ± 0.21 mm), height allotype 4.7 mm, paratypes 4.2 – 5.2 (x = 4.6 ± 0.42 mm), width allotype 3.9 mm. Variability. In males the truncated terminal facet of the rostrum is not always at 90 o to the rostral axis, but may be as low as 75 o. The rostrum may be expanded terminally by about 20–25%, rather than 30%, and the dorsal carina is not always bold, hardly standing expressed beyond the rostral dorsal surface. On the clasper, the hump on the basal part of endite VI is not always so distinct as in the type, the endites V and IV are variable in shape and setation, and the spines on the distomedial corner of endite III vary from six to nine. Interestingly the sites in the distributional outlier of north Queensland, mostly have 22–26 large setae in the setal row on endite V and only five to seven teeth on the distomedial corner of endite III, whereas the average is about 15 setae and seven to nine teeth over most of the range in WA and SA. In females, the rostrum may not be as wide terminally as in the type and on the posteriolateral plate the size and shape of the lateral lobes are variable, but there is always only one dorsal digitiform process anteriorly. Distribution. L. magdaleanae sp. nov. occurs ubiquitously in deeper gnammas throughout the Wheatbelt (e.g. Fig. 9C) and adjacent Goldfields of Western Australia (except the strip from Beacon to Trayning occupied by L. baylyi sp.nov. ― see above). It also occurs in pit gnammas throughout the northern Eyre Peninsula, Gawler Ranges and northwestern half of South Australia and the southwestern Northern Terrritory, and sporadically in gnammas in the central deserts of Western Australia. L. magdaleanae sp. nov. is also established in northern Queensland but not in gnammas; these occurrences and habitat choice seem incongruous considering its widespread occurrence in gnammas in WA and western SA. Perhaps these northern Queensland records are of a separate species, but so far they are only distinguishable by a slightly different count of setae of endite V and of spines on the distomedial corner of endite III. Specimens from the Wheatbelt and Goldfields of Western Australia were previously misidentified by MZ and the author as L. macleayanus (see Bayly et al 2012; Passaq et al. 2011; Timms 2006, 2012; Zofkova 2007).Published as part of TIMMS, BRIAN V, 2013, A Revision of the Australian species of Lynceus Müller, 1776 (Crustacea: Branchiopoda: Laevicaudata, Lynceidae), pp. 501-533 in Zootaxa 3702 (6) on pages 521-524, DOI: 10.11646/zootaxa.3702.6.
Parartemia yarleensis Timms & Hudson, 2009, n. sp.
No full textParartemia yarleensis n. sp. (Figure 7) Type material. Holotype. Male, SOUTH AUSTRALIA, Yarle Lake system, most likely Choolalie Lake (30 o 17 ’ 20 ”S, 131 o 31 ’00”E), (approx 15 km S of Maralinga), 16 September 1979, J. Glover, SAM C 6779; Allotype. Female, same collecting data as holotype, SAM 6782; Paratypes. Two males and two females, same collecting data as holotype, SAM C 6781. Other material. About 20 males and five females, SOUTH AUSTRALIA, Yarle Lakes, most likely Choolalie Lake (30 o 17 ’ 20 ”S, 131 o 31 ’00”E), (approx 15 km S of Maralinga), 16 September 1979, J. Glover, SAM C 6782; many males, SOUTH AUSTRALIA, Lake Labyrinth, (30 ° 41 ’ 30 ”S, 135 ° 11 ’ 55 ”E), (approx 27 km NW Kingoonya), 12 June 2004, P. Hudson & G. Tomlinson, SAM C 6783; many juveniles, SOUTH AUSTRALIA, “Carters Well Lake”, (30 ° 51 ’01”S, 134 ° 58 ’ 35 ”E), (approx 42 km ESE of Tarcoola), 13 June 2004, P. Hudson & G. Tomlinson, SAM C 6808; many juveniles, SOUTH AUSTRALIA, Lake Harris, (31 o 08’ 51 ”S, 135 o 18 ’ 30 ”E), (approx 20 km S Kingoonya), 19 March 2003, P. Hudson and G. Tomlinson, SAM C 6786; many juveniles; SOUTH AUSTRALIA, Ironstone Lagoon, (31 ° 42 ’S, 137 ° 13 ’ 30 ’’E), (approx 65 km SE of Woomera), 1 February, 2007, P. Hudson & G. Tomlinson, SAM C 6784; many juvenile males, SOUTH AUSTRALIA, Lake Gilles, (33 °01’ 25 ”S, 136 ° 36 ’07”E), (approx 20 km NE of Kimba), 6 August 2005, P. Hudson, SAM C 6785. Description. Male. Length 18 mm (head plus thorax 7.5 mm, abdomen 10.5 mm). Head (Fig. 7 A) with first antenna filiform, a little longer than eye plus peduncle. Proximal antennomeres of second antenna fused basially at an angle of about 75 degrees from body axis. Ventral edge of fused antennomeres with paired ventral processes (VP, Fig 7 A) three times longer than deep and with length of lateral edge about half that of medial edge. Lateral corner of ventral process protruding slightly, frontal edge only slightly concave, medial corner rounded, and all edges with a few denticles. Small conical mound (CM, Fig, 7 B) on ventroposterior surface under lateral corner. Area between ventral processes trapezoid, with a short digitiform medial process (MP, Fig 7 A) less than one quarter of depth of medial edge of transverse process. Anterior surface of fused antennomere with paired ridges parallel to body axis and terminating in anterior processes (AP, Fig 7 A) with a broad base but digitiform apical half. Anterioventral surface of fused antennomere marked in sunken polygons (SP, Fig 7 A). Distal second antenna antennomere subcylindrical, slightly concavely curved and tapering to a sharp apex. Length about 1.6 times proximal antennomere. Labrum without a spine. Thorax gradually widening posteriorly to 11 th segment, mainly by increasingly larger lateral lobes, tending asymmetrical (i.e. maximum width displaced from middle of lobe) segments 7–10 (L, Fig. 7 C). Genital segments narrower than 11 th thoracic segment and abdomen continually narrowing so that 6 th segment about 2 / 3 rds width of first segment. Thoracopods (Fig 7 E) of the Parartemia type as described for P. acidiphila n. sp., except for fewer posterior setae on endites 1 +2, 3, endopodite and exopodite (c.45, 11, 26 and 35 respectively). Posterior setae on medial edge of endopodite more numerous than usual (11 cf c. 7), particularly strong, curved apically and with a short pecten apically (EPS, Fig 7 E). Paired gonopods with a spines subapically and a short digitiform processes (DP, Fig. 7 D) on the shoulder of wider basal part, neither hooked. No type specimens with gonopods everted. Abdominal segments serially decreasing in diameter and increasing in length posteriorly. Sixth segment about twice as long as first segment. Cercopods subequal in length to sixth abdominal segment and with setae medially and laterally. Description. Female. Length 11.3 mm. Head (Fig. 7 F) with first antenna filiform, about length of eye plus peduncle. Second antenna about twice length of eye plus peduncle, flattened and with its widest area about two-thirds its length towards the apex, followed by a marked narrowing to an acute apex on the posterior side. Apex curved like the recurved labrum spine. Thoracic segments (Fig. 7 G) expanded laterally by distinct lobes, increasing in size and degree of asymmetry (i.e. displacement of widest point from centre of lobe) serially segments 5 to 9. Segment 10 with very different lateral lobes, expanded anteriorly, free in allotype and dorsal to lobe of 9 th segment. Segment 11 with a narrow triangular lateral lobe. In lateral profile (Fig. 7 H), segments 9 to 11 not raised dorsally as much as anterior segments. Segment 8 swollen dorsally. Paired brood pouches separate, oval, unlobed but joined ventrally to a gonoduct shorter than the depth of the brood pouch. Each pouch with numerous spherical smooth surfaced eggs. Thorax with only 10 pairs of thoracopods and 10 th thoracopod reduced to about half size of other thoracopods. Anterior setae of 10 th thoracopod typical, but few posterior setae on all parts and lacking an epipodite but with reduced praepipodite (Fig. 7 I). Fifth thoracopod as in male. Abdomen as in male, but surface denticulate. Etymology. The species is named after the type locality. Variability. Though this species is known from a few sites, many of these had only juvenile males, so variation between sites is hardly studied. Within the type locality some males had more bulbous lateral corners to their ventral processes than the holotype. Among females, the second antennal apex is not always curved and the lateral lobe of the 10 th thoracic segment varied within and between sites, with it being attached to the lobe of the 9 th segment, often in younger females. Differential diagnosis. Male P. yarleensis has a head (specifically a medial process and ventral processes) broadly similar to those of P. informis, P. serventyi and P. contracta, but unlike those species, has distinct thoracic lobes. These lobes are not as large as in P. cylindrifera and in Parartem ia sp. g (as illustrated in Timms 2004), but broadly similar to those of P. auriciforma n. sp. and P. triquetra n. sp. While the latter two species occur in the same general area as P. yarleensis n. sp., they are easily distinguished as neither have the medial process between the ventral processes as in P. yarleensis n. sp. Female P. y a r l e e n s i s n. sp. also share many features with local species P. auriciforma n. sp. and P. triquetra n. sp., such as thoracic lateral lobes, round to oval brood chambers and greatly reduced or absent 11 th thoracopods. However, P. yarleensis is distinctive by reason of superficial dorsal swelling on the 8 th segment (somewhat like that in P. serventyi), and the bulbous lateral lobes of segment 10. It cannot be confused with P. serventyi as this species has posterior lobes on its brood pouches, no thoracic lateral lobes, and paired dorsolateral swellings on segment 9. Type locality. Yarle Lakes is a series of lakes south of Maralinga that fill episodically and are ‘very saline’ according to collecting data. There is some doubt over which one of the lakes was sampled, but examination of the field notes of J. Glover’s participants of the field trip, the probable collection site of Choolalie Lake was established on the basis of sketch map of the area. FIGURE 7. Parartemia yarleensis n. sp. Male A-E, Holotype; Female, F-I Allotype; both from Yarle Lakes, most likely Lake Choolalie, SA. A, anterior view of head with first and second antennae (VP = ventral processes, AP = anterior processes, MP = medial process, SP = sunken polygons); B, posterior view of one side of basal antennomere of second antenna showing the conical mound (CM) behind the ventral process; C, dorsal view of body from head to cercopods showing segmental lobes (L); D, gonopods with genital segments showing digitform processes (DP); E, Fifth thoracopod with pectin bearing endopod posterior setae labelled (EPS); F, Lateral view of head; G, dorsal view of thoracic segments 4-11, genital segments, brood pouches and first two abdominal segments; H, lateral view of posterior thorax and adjacent brood pouch; I, 10 th thoracopod. Scale bars 1 mm. Distribution and ecology. P. yarleensis n. sp. is known from a broad arc of lakes extending from Woomera to Maralinga in the northwest of South Australia (Fig. 4). The collection from Ironstone Lagoon also contains P. m i n u t a, a species smaller than P. y a r l e e n s i s (P. m i n u t a males mean 8.7 mm, 10 specimens, females mean 5.2 mm, 10 specimens). Such a congeneric occurrence is rare in Parartemia (A. Savage, pers. comm.; B. Timms, unpublished data) possibly because most species of Parartemia do what P. zietziana does and that is they live on resuspended organic matter (Marchant and Williams, 1977), as opposed to algal eating Branchinella, in which congeneric occurrence of different sized species and hence filtering ranges, are common (e.g. Timms & Sanders, 2002).Published as part of Timms, Brian V & Hudson, Peter, 2009, The brine shrimps (Artemia and Parartemia) of South Australia, including descriptions of four new species of Parartemia (Crustacea: Anostraca: Artemiina), pp. 47-68 in Zootaxa 2248 on pages 60-63, DOI: 10.5281/zenodo.19074
Eulimnadia canalis Timms, 2016, sp. nov.
No full textEulimnadia canalis sp. nov. (Figs 3 G, 7) Etymology. The specific name ‘canalis’ is Latin and means canal or groove and refers to the egg of this species which has many long grooves in the tertiary layer. Type locality. New South Wales, 120 km NE of Bourke, Bloodwood Station, a clay pan locally known as ‘Dead Ram,’ 5 km W of homestead, 29 o 31 ’ 46.7 ”S, 144 o 52 ’ 2.5 ”E, 21 February 2011, BVT. Type material. Holotype. Hermaphrodite deposited in Australian Museum, 6.8 mm long, 4.6 mm high, registration number AM P 97832. Paratypes. Hermaphrodites deposited in Australian Museum, 7.3 mm long by 5.0 mm high and 6.6 mm by 3.9 mm, registration number AM P 97833. Other material. New South Wales: Ten hermaphrodites, 120 km NE of Bourke, Bloodwood Station, Homestead Blackbox Swamp, 29 o 31 ’ 29 ”S, 144 o 53 ’ 28 ”E, 21 February 2011, BVT and MS, AM P 97834. Diagnosis. Egg with about 35 narrow, deep grooves, length of each about 40 % the egg diameter. 18 trunk segments. Telson with about 15 dorsal spines and cercopod with about 16 long (about 2.5 x cercopod diameter) setae. Description. Egg. (Fig 3 G) Spherical, 148 Μm (range 144–153 ìm, n= 5) in diameter, with about 35 narrow, deep grooves each about 40 % of the diameter and most curved longitudinally. Ridges between grooves broad, rounded. Tertiary layer spongiform and and surface microporous. Hermaphrodite. Head (Fig 7 B) with ocular tubercle prominent, the compound eye occupying most (ca. 70 %) of it. Rostrum broadly rounded protruding a little less than ocular tubercle with ocellus almost as large as the eye basodorsally. Frons-rostrum angle about 110 o. Dorsal organ posterior to eye by a little more than is height; height about two-thirds ocular tubercle height. First antennae a little longer than peduncle of second antennae and with about five lobes each with many small sensory setae. Second antennae with 9 antennomeres dorsally and 10 ventrally, each antennomere with 1–7 dorsal spines and 3–6 ventral setae, most with 4–6 spines and 4–5 setae. Basal and two distal antennomeres with most aberrant numbers. Carapace (Fig 7 A) pellucid, elongated oval with dorsal edge vaulted, maximum height at about 2 / 5 ths length. About 4 growth lines. Adductor muscle about 40 o to long axis of carapace, but difficult to see. Thoracopods Eighteen a pairs of typical Eulimnadia structure. Trunk dorsum with 1–9 setae terminally, these setae few, short and stout on distal few segments, numerous and longer on segments 8–15 and hardly any setae on anterior trunk segments 1–7. Telson with 15 pairs of dorsal spines, anterior spines, particularly 4–7 more spaced than posterior spines; most spines with denticles. Caudal filaments on a mound between spines 4 and 5. Telsonic floor posterior to mound with a marked declivity, then sloping away gently to cercopod base. Cercopod a little longer than telson with basal 80 % hardly narrowing and with about 16 setae of moderate length, each about twice its diameter and feathered. Distal 20 % of cercopod narrowing to an acute apex and with many denticles dorsolaterally. The two zones of the cercopod demarked with a small spine. Prominent spiniform projection beneath the cercopod at the ventroposterior corner of the telson. Variability. With only three specimens available and all from one site, the full range of variation is unrecorded. Flagella of second antennae had 8–10 antennomeres, average near 9. In some specimens there were few dorsal spines and ventral setae. Telsonic spines ranged from 13 to 16 with those at about 3–7 always spaced a little more. Cercopod setae varied in number from 14–18, with sometimes the first one or two shorter than the rest. Comments. This species besides occurring at two sits on Bloodwood Station in the NSW part of the Paroo, has a distinctive egg which was seen in material from a swamp south of Thargomindah in the adjacent Bulloo catchment but not assignable for sure to respective specimens. Otherwise it is most similar to E. dahli and E. taroomaensis sp. nov. in that it has many (> 14) moderate to long cercopod setae. However E. dahli has> 18 setae and 20 trunk segments whereas E. canalis sp. nov. has <16 setae and 18 trunk segments, and in E. taroomaensis sp. nov. the setae are shorter distally while in E. canalis sp. nov. all setae are similar in length. Distribution. Paroo and Bulloo catchments, northwestern NSW and southwestern Queensland.Published as part of Brian V Timms, 2016, A partial revision of the Australian Eulimnadia Packard, 1874 (Branchiopoda: Spinicaudata: Limnadiidae), pp. 351-389 in Zootaxa 4066 (4) on pages 363-365, DOI: 10.11646/zootaxa.4066.4.1, http://zenodo.org/record/26423
Scale-dependent influence of pre-existing basement shear zones on rift faulting : a case study from NE Brazil
No full textRifting of continental crust initiates faults that are commonly influenced by pre-existing structures. We document newly identified faults cutting Precambrian units in the interior of the NE Brazilian margin to assess the effects of structural inheritance on both rift geometry and fault architecture. Stratigraphic and structural data indicate that the faults were active in the main phase of rifting of Gondwana. The influence of pre-existing structures on the Mesozoic rift faulting is scale dependent. Regionally, the faults trend parallel to subvertical, crustal-scale Brasiliano (c. 750–540 Ma) shear zones. Mylonitic foliations and broadly distributed low strain in the lower crust indicated by shear-wave splitting controlled the overall orientation and kinematics of the rift faults. However, outcrop observations of the faults show that at scales up to hundreds of metres, mylonitic foliations have little influence on fault architectures. Faults cross-cut shear zones and do not commonly utilize foliation planes as shear fractures. Instead, slip zones and fractures have a range of orientations that form acute angles to the local foliation orientation. This observation explains the range of focal mechanisms associated with seismicity that coincides with ancient shear zones in intra-continental areas
Dynamics of Network Formation Processes in the Co-Author Model
No full textThis article studies the dynamics in the formation processes of a mutual consent network in game theory setting: the Co-Author Model. In this article, a limited observation is applied and analytical results are derived. Then, 2 parameters are varied: the number of individuals in the network and the initial probability of the links in the network in its initial state. A simulation result shows a finding that is consistent with an analytical result for a state of equilibrium while it also shows different possible equilibria.Dynamics, Network, Game Theory, Model,Simulation, Equilibrium, Complexity
Examination of the financial and economic impact US exchange rate volatility has on fixed income securities for Chinese investors
No full textCriminally Incompetent Academic Misinterpretation of Criminal Data-and how the Media Pushed the Fake News
No full textOn 17 Jan 2018 multiple news sources (e.g. see here, here, and here) ran a story about a new research paper that claims to expose both the inaccuracies and racial bias in one of the most common algorithms used by parole boards to predict recidivism (i.e. whether or not a defendant will re-offend). The research paper was written by the world famous computer scientist Hany Farid (along with a student Julia Dressel). But the real story here is that the paper’s accusation of racial bias (specifically that the algorithm is biased against black people) is based on a fundamental misunderstanding of causation and statistics. The algorithm is no more ‘biased’ against black people than it is biased against white single parents, old people, people living in Beattyville Kentucky, or women called ‘Amber’. In fact, as we show in this brief article, if you choose any factor that correlates with poverty you will inevitably replicate the statistical ‘bias’ claimed in the paper. And if you accept the validity of the claims in the paper then you must also accept, for example, that a charity which uses poverty as a factor to identify and help homeless people is being racist because it is biased against white people (and also, interestingly, Indian Americans). The fact that the article was published and that none of the media running the story realise that they are pushing fake news is what is most important here. Depressingly, many similar research studies involving the same kind of misinterpretation of statistics result in popular media articles that push a false narrative of one kind or another
Il tesoro della Sardegna ne' bachi e ne' gelsi
No full textA critical edition of Antonio Purqueddu, Il tesoro della Sardegna ne' bachi e ne' gelsi, a didactic poem – written in Campidanese Sardinian with a version in Italian by the same author – published in 1779.
The Introduction of the editor sets this work into its historical seventeenth-century context with reference to Italian and European culture. The editor brings the specific ideality and political plan of the author to light, as is done with the other didactic authors living in Sardinia during the second half of the XVIII century
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