116,905 research outputs found
Top Management Team Diversity: A systematic Review
No full textEmpirical research investigating the impact of top management team (TMT)
diversity on executives’ decision making has produced inconclusive results.
To synthesize and aggregate the results on the diversity-performance
link, a meta-regression analysis (MRA) is conducted. It integrates more
than 200 estimates from 53 empirical studies investigating TMT diversity
and its impact on the quality of executives’ decision making as reflected
in corporate performance. The analysis contributes to the literature by
theoretically discussing and empirically examining the effects of TMT diversity
on corporate performance. Our results do not show a link between TMT
diversity and performance but provide evidence for publication bias. Thus,
the findings raise doubts on the impact of TMT diversity on performance
Opamyrma Yamane, Bui et Eguchi 2008
No full text<i>Opamyrma</i> Yamane, Bui et Eguchi, 2008 <p> <b>Taxonomy.</b> The genus <i>Opamyrma</i> was established for a single species, <i>O. hungvuong</i>, and is morphologically very close to <i>Apomyrma</i> known from the Afrotropical region (Yamane <i>et al.</i> 2008).</p> <p> <b>Morphology.</b> Worker presumably monomorphic; body long and slender, with long legs; head in full-face view subrectangular, and somewhat flattened dorsoventrally; preoccipital carina complete, almost encircling the head slightly before its posterior margin; frontal lobe, frontal carina and antennal scrobe absent; median part of clypeus rather clearly divided into posterior horizontal portion and anterior steep slope; the posterior portion distinctly separated from frons with a continuous carina, and broadly inserted between antennal sockets; lateral part of clypeus narrow from front to back; mandible slender, with long but bluntly tapered apical tooth followed by a trapezoidal lobe and three inconspicuous teeth; labrum on its outer face with at least two rows of peg-like denticles; eye absent; antennal sockets completely exposed in full-face view, located in a large, roundly excavated area whose anterior wall is steep just behind posterior margin of clypeus; antenna 12-segmented, gradually incrassate from segment II to XII; mesosoma slender, in lateral view flattened dorsally; promesonotal suture present and flexible; metanotal groove absent dorsally; propodeum unarmed; orifice of propodeal spiracle round, situated relatively low on lateral face of propodeum; propodeal lobe much reduced; mid- and hind tibiae each with a reduced barbulate anterior spur in front of a well-developed pectinate posterior spur; waist consisting of a single segment (petiole); petiole extremely elongate, virtually without anterior peduncle, narrowly attached to abdominal segment III; tergosternal sutures of petiole present; petiolar spiracle located anteriorly on lateral face of petiole at its mid-height; gaster (consisting of abdominal segments III–VII) extremely elongate; abdominal segment III above helcium with free anterior face; spiracles on segments V–VII concealed by the preceding segments; segment VII longest among the segments III–VII; pygidium and hypopygium unarmed laterally and posteriorly.</p> <p> <b>Differentiation.</b> The worker of <i>Opamyrma</i> is easily distinguished from that of the other Vietnamese genera of Amblyoponinae by a combination of the following features: petiole narrowly attached to abdominal segment III (gastral segment I); abdominal segment III above helcium with free anterior face; frontal lobe completely absent, thus antennal socket in full-face view fully exposed.</p> <p> <b>Vietnamese species (1 sp.).</b></p> <p> <i>O. hungvuong</i> Yamane, Bui et Eguchi, 2008. Type locality: Huong Son Forest (so far been known only from the type series).</p> <p> <b>Bionomics.</b> Unknown.</p>Published as part of <i>Eguchi, Katsuyuki, Viet, Bui Tuan & Yamane, Seiki, 2014, Generic Synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), Part II — Cerapachyinae, Aenictinae, Dorylinae, Leptanillinae, Amblyoponinae, Ponerinae, Ectatomminae and Proceratiinae, pp. 1-46 in Zootaxa 3860 (1)</i> on pages 24-25, DOI: 10.11646/zootaxa.3860.1.1, <a href="http://zenodo.org/record/287059">http://zenodo.org/record/287059</a>
Parvimyrma sangi Eguchi & Bui, 2007, sp. nov.
No full textParvimyrma sangi sp. nov. (Figs. 1–10) Holotype worker: Tay Yen Tu N. P., 21 ° 10 ’ 11 ”N, 106 ° 43 ’06”E, 435 m alt., Bac Giang Prov., N. Vietnam, 28 May 2004 (K. Eguchi leg., colony Eg04-VN- 138) [IEBR]. Paratypes: 42 pinned and 2 slide-mounted workers from the same colony as holotype [IEBR, BMNH, MCZC, MHNG, MNHA, ACEG]. Worker description. Tiny species with characteristics given in the generic diagnosis. Body pale yellowish brown, much depigmented, covered with short standing hairs. Head in full-face view roughly elongaterectangular, in profile thin dorsoventrally with flattened dorsal and ventral margin; the dorsum of head weakly rugoso-reticulate except almost smooth anteromedian part of frons; the lateral face of head weakly rugosoreticulate; clypeus largely smooth, with its anteromedian margin truncate; outer surface of mandible smooth; mandibular teeth triangular and sharp, gradually reduced in size from the apical teeth to the basal teeth; antennal scape short, reaching only 7 / 10 – 3 / 4 of the distance from the anterior margin of clypeus to the posterior margin of head (Fig. 2); antennal segments III–IX much shorter than broad; the apical antennal segment ca. 3 times as long as the preapical segment; mesosoma smooth except lower part of mesopleuron which is very weakly reticulate; gaster entirely smooth. Worker measurements and indices. Holotype: HL 0.37 mm, HW 0.26 mm, SL 0.21 mm, ML 0.42 mm, FL 0.19 mm, CI 71, SI 81, FI 71. Paratypes (n= 4): HL 0.37 mm, HW 0.26–0.27 mm, SL 0.21 mm, ML 0.40–0.41 mm, FL 0.19–0.20 mm, CI 71–73, SI 78–79, FI 71–74. Bionomics. The type series was obtained from one of ten cheese bait traps (small plastic tubes with several entrances containing powdered cheese as bait) buried ca. 10 cm underground in a well-developed forest at ca. 435 m alt. The circumstantial evidence as well as its morphological features (depigmentation and flat body without eyes) suggest that Parvimyrma sangi is a subterranean nester and forager.Published as part of Eguchi, Katsuyuki & Bui, Tuan Viet, 2007, Parvimyrma gen. nov. belonging to the Solenopsis genus group from Vietnam (Hymenoptera: Formicidae: Myrmicinae: Solenopsidini), pp. 39-47 in Zootaxa 1461 on pages 44-46, DOI: 10.5281/zenodo.27373
Opamyrma Yamane, Bui & Eguchi, 2008, gen. n.
No full textOpamyrma gen. n. (Figs. 1–12) Type species. Opamyrma hungvuong sp. n. Worker description. Preoccipital carina complete, almost encircling the head slightly before its posterior margin (“poc” in Fig. 4). Venter of head with a distinct and complete median furrow, with each anterolateral corner forming a process (“alc” in Fig. 3). Clypeus posteriorly margined with a distinct continuous carina (“pcc” in Fig. 3); median part of clypeus rather clearly divided into posterior horizontal portion and anterior steep slope; the posterior portion broadly inserted between antennal sockets, extending anteriorly to the level of posterior margin of the sockets; lateral part of clypeus narrow from front to back. Mandibular base with closed trulleum (“trl” in Fig. 3). Labrum on its outer face with at least two rows of peg-like denticles, each with more than 10 denticles (“lpd” in Fig. 3). Eye absent. Frontal lobe absent. Antennal sockets completely exposed in full-face view, directing almost dorsad, located in a large, roundly excavated area whose anterior wall is steep just behind the posterior margin of clypeus; the area not clearly defined posteriorly. Antenna 12 - segmented, gradually incrassate from segment II to XII. Mesosoma elongate, with a single furrow (“msf” in Figs. 6 & 7) which is deep and flexible and separates pronotum from the remaining part of mesosoma. Metapleural gland bulla round, occupying posterior twofifths of ventrolateral part of the pleuron; metapleural trench running below the bulla. Junction of dorsal and posterior faces of propodeum round without any transverse carina; posterior face of propodeum laterally without spines/carinae. Propodeal spiracle situated relatively low on the side of propodeum, near the weak furrow separating metapleuron from lateral side of propodeum. Propodeal lobe present, low and round. Mid- and hind tibiae each with a reduced barbulate anterior spur (“ats” in Fig. 8) and a well-developed pectinate posterior spur (“pts” in Fig. 8). Pretarsal claws simple, without teeth. Waist consisting of a single segment (petiole); petiole elongate, narrowly attached to abdominal segment III (gastral segment I), virtually without anterior peduncle; tergo-sternal sutures of petiole present as longitudinal furrows on ventrolateral edges that meet medially at 1 / 3 length of petiole from the base (“tss” in Fig. 10); the sternite of petiole reduced to a small posteroventral sclerite, bounded by the conspicuous tergo-sternal sutures; petiolar spiracle located anteriorly on the lateral face of petiole at its mid-height. Gaster very long, laterally compressed, especially in posterior portion, in profile highest at the posterior end of abdominal segment VI (“absg-VI” in Fig. 11). Segment III (“absg-III” in Fig. 11) seen from above longer than broad, narrowed basally, longer than segments IV, V and VI, having a free anterior face above the helcium; anteriormost part of abdominal sternite III (“abs-III” in Fig. 11) produced anteriad to the same level as the anteriormost part of tergite III (“abt-III” in Fig. 11). Segment IV with differentiated presternite (“ps-IV” in Fig. 11). Spiracles on segments V–VII concealed by the preceding segments. Segment VII (“absg-VII” in Fig. 11) longest among the segments III–VII. Pygidium (“abt-VII” in Fig. 11) and hypopygium (“abs-VII” in Fig. 11) unarmed.Published as part of Yamane, Seiki, Bui, Tuan Viet & Eguchi, Katsuyuki, 2008, Opamyrma hungvuong, a new genus and species of ant related to Apomyrma (Hymenoptera: Formicidae: Amblyoponinae), pp. 55-63 in Zootaxa 1767 on page 56, DOI: 10.5281/zenodo.27426
Synapsis puluongensis Bui & Bonkowski 2018, sp. nov.
No full textSynapsis puluongensis sp. nov. (Figs 1 A–F, 2A,C,E) Type locality. Vietnam, Thanh Hoa Province, Puluong Nature Reserve, 20º28′54″N 105º14′31″E, 950 m a.s.l. Type material. HOLOTYPE: ♁ ‘ VIETNAM | THANH HOA Prov. | Pu Luong Nat. Reserve, near Ban Ba vill. | 20º28’54’’N 105º14’31’’E, 950 m | primary forest | 10.–25.iv.2016 | Van Bac Bui leg.’ (VNUF). PARATYPES (five specimens): ♁, ‘ VIETNAM | THANH HOA Prov. | Pu Luong Nat. Reserve, near Ban Ba vill. | 20º28’55’’N 105º14’29’’E, 958 m | primary forest | 10.–25.iv. 2016 | Van Bac Bui leg.’ (VNUF); ♀, ‘VIETNNAM | THANH HOA Prov. | Pu Luong Nat. Reserve, near Ban Ba vill. | 20º28’54’’N 105º14’29’’E, 954 m | primary forest | 10.–25.iv.2016 | Van Bien Nguyen leg.’ (VNUF); 3♀♀, ‘ VIETNAM | THANH HOA Prov. | Pu Luong Nat.Reserve, near Ban Ba vill. | 20º28’56’’N 105º14’28’’E, 956 m | primary forest | 10.–25.iv.2016 | Van Bac Bui leg.’ (2 PLNR, 1 NMPC). Diagnosis. Body length 17.2–18.5 mm, body width 10.4– 11.5 mm; hypomeral cavities not covered by macrosetae; mesepisternal cavities absent; genae unexpanded; frons unarmed; anterolateral angles of pronotum not protruding; elytral striae strongly punctate; elytral intervals impunctate, convex and glossy, interval 2 near base not swollen; ventral sides of metafemora densely punctate. Description of holotype (male). Body length 18.38 mm, body width 11.32 mm. Whole surface black, very shiny and glabrous. Margins of legs and pronotum with reddish- brown macrosetae. Head broad (HeadL 3.67 mm, HeadW 7.44 mm), extremely rugose anteriorly; posterior part sparsely punctate; fine punctures surrounding eyes. Anterior margin of clypeus bidentate, V-shaped, flexed upwards, with few reddish setae. Distance between apices of clypeal denticles (DDC) 1.43 mm. Genae rectangular, quite distinctly separated from clypeus and frons by well-defined suture with sculptural punctures. Genae closely and evenly punctate, with scanty reddish macrosetae. Frons glabrous and very unevenly punctate. Area surrounding eyes bearing more closely spaced and coarser punctures than base. Frons unarmed, only slightly swollen. Antennae composed of 9 antennomeres. Antennomere I 1.34 mm in length, longer than antennomeres II–IV combined (1.25 mm in length). Antennomeres I and II darker, bearing more yellow macrosetae than remaining antennomeres. Prothorax. Pronotum transverse (PronL 4.9 mm, PronW 10.08 mm), widest at anterior quarter, with two distinct lateral carinae at each side. Area between carinae black, matte, glabrous and not punctate. Outer margin of outer carina with dense reddish-brown macrosetae. Anterolateral angles short and not protruding. Punctures not evenly distributed, denser at sides. Only small area at anterior edge of pronotal collar microrugose. Hypomeral cavities present but shallow, sparsely punctate and not covered with macrosetae. Meso-metaventrum quite smooth, with a few scattered fine punctures at its anterior end, bearing posterior median groove and deep excavation near metacoxae. Pterothorax. Elytra (ElyL 11.4 mm, MWoI123: 2.51 mm) convex, very shiny, deeply striate; elytral striae strongly, densely punctate (DP10, 15: 1.03 mm); intervals smooth and impunctate. Interval 2 near base not swollen. Mesepimeron and metepisternum flat, granulose and without macrosetae. Legs. Protibia (ProTiL 3.30 mm, ProTiW 2.35 mm, ProTiSL 1.21 mm) tridentate, terminal tooth as long as protibial spur and nearly as long as protibial tarsus. Mesotibia (MesoTiL 3.34 mm, MesoTiW 1.33 mm, 1 stMesoTiSL 2.09 mm, 2 ndMesoTiSL 0.9 mm) and metatibia (MetaTiL 4.95 mm, MetaTiW 1.27 mm, MetaTiSL 1.55 mm) with red scanty macrosetae and slender spurs. Metatarsomeres nearly similar in size (MetaTaL 3.72 mm, MetaTa1L 1.08 mm, MetaTa1W 0.68 mm, MetaTa5W 0.32 mm). Abdomen and pygidium. Abdominal ventrites opaque, sparsely punctate, and narrower at midline. Pygidium (PyL 2.46 mm, PyW 4.5 mm) feebly convex, densely and transversely punctate and scabrous. Aedeagus (Figs 1E, F). Phallobase length 3.57 mm in lateral view, with strong swelling in middle of basal suture. Parameres length 2.19 mm (in lateral view), triangle-shaped. Phallobase and parameres forming angle> 130º. Sexual dimorphism. Females differ from males in their weaker elytral striae, and meso- and metatrochanters with sparser reddish-brown macrosetae (absent in some specimens). Sexes also differ in the shape and strength of the metafemoral tooth, which is stronger in males. Compound eyes black in females but reddish brown in males. Morphometrics. See Table 1. Differential diagnosis. Synapsis puluongensis sp. nov. belongs to the S. birmanica group, as indicated by a combination of the following characters: hypomeral cavities present, genae unexpanded, frons unarmed, mesepisternal cavities absent, and upper longitudinal carina of male metatibia without brush of rusty setae. Species of the S. birmanica group may be clearly distinguished from those of S. ovalis, S. brahmina and S. tmolus groups by the presence of hypomeral cavities. The S. ritsemae group has expanded genae, in which it differs from the species of the S. birmanica group whose genae are unexpanded. Synapsis puluongensis sp. nov. can be distinguished from other known species of the group by the following characters: in S. puluongensis the elytral interval 2 is not swollen near the base (swollen in S. yama from northern and central Vietnam and Laos, S. horaki from northern Vietnam, S. dickinsoni from northern Thailand: Phukieo, S. ochii from northern Thailand: Chiang Mai and in S. masumotoi from Taiwan). Characters on the metafemora and elytral striae clearly differentiate S. puluongensis sp. nov. from the other species of the S. birmanica group recorded in Vietnam: both S. puluongensis sp. nov. and S. horaki have densely punctured metafemora on the ventral side, while S. yama has no punctures on the metafemur. In addition, S. puluongensis sp. nov. has coarse and closely spaced punctures on the elytral striae, which are absent or extremely weak in S. horaki (Figs 2 A–D). Synapsis puluongensis sp. nov. has hypomeral cavities without macrosetae, which distinguishes it from S. birmanica (hypomeral cavities are covered by a brush of rusty macrosetae). The new species has deep striae, whereas in S. birmanica the striae are feeble (Figs 2 E–F). Synapsis puluongensis sp. nov. is morphologically similar to S. naxiorum in its black and shiny dorsal side. However, the new species can be distinguished from S. naxiorum in having more punctures on the ventral side of the metafemora; elytral striae more densely punctate, intervals not punctate, and hypomeral cavities devoid of rusty setae (Figs 2A,G). The entire surface of S. puluongensis sp. nov. is black and shiny, in contrast to the opaque surface of S. punctata from Myanmar and S. roslihashimi from Malaysia. In addition, S. puluongensis sp. nov. has convex intervals, whereas S. roslihashimi and S. punctata have flat or only weakly convex intervals. In S. punctata and S. roslihashimi all margins of intervals are punctate, whereas they are impunctate in the new species. The new species can also be distinguished from S. punctata and S. roslihashimi by the absence of hypomeral rusty macrosetae. Etymology. The specific epithet puluongensis refers to the name of the type locality, Nature Reserve Puluong, Thanh Hoa Province, central Vietnam; adjective. Biology. The new species was collected in primary forests on limestone bedrock. The primary forests are characterized by a complex structure with various storeys, comprising an upper storey with emergent trees more than 35 m tall, belonging to Dipterocarpaceae and Combretaceae, a dominant lower storey (various tree species from 15 to 30 m tall), and a brush layer on the forest floor containing various herbs (Urticaceae, Araceae, Begoniaceae), lianas and parasitic plants (Connaraceae, Fabaceae, Orchidaceae, Loranthaceae).Published as part of Bui, Van Bac & Bonkowski, Michael, 2018, Synapsis puluongensis sp. nov. and redescription of S. horaki (Coleoptera: Scarabaeidae), with a key to Vietnamese species, pp. 407-418 in Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) (Acta. Ent. Mus. Natl. Pragae) 58 (2) on pages 408-413, DOI: 10.2478/aemnp-2018-0032, http://zenodo.org/record/450489
author-bios-SRD-19-0063.R1 – Supplemental material for The Network Structure of Police Misconduct
No full textSupplemental material, author-bios-SRD-19-0063.R1 for The Network Structure of Police Misconduct by George Wood, Daria Roithmayr and Andrew V. Papachristos in Socius</p
Opamyrma hungvuong Yamane, Bui & Eguchi, 2008, sp. n.
No full textOpamyrma hungvuong sp. n. (Figs. 1–12) Type material. Holotype (worker): 21 Feb. 2000, Rao An, Son Kim II Commune (18 ° 31 'N; 105 ° 27 'E), Huong Son District, Ha Tinh Province, northern part of Central Vietnam, leg. T.V. Bui (IEBR). Paratype: 1 worker, same data as in the holotype (KMNH). Measurements and indices (holotype and paratype; those for paratype shown in parentheses). Head length (as measured from the anterior margin of clypeus to the posterior margin of head in full-face view) 0.73 mm (0.71); head width (maximum width of head in full-face view) 0.55 mm (0.55); cephalic index (head width/head length x 100) 75 (77); scape length (length of antennal scape excluding the basal condylar bulb) 0.38 mm (0.38); scape index (scape length/head width x 100) 69 (69); mesosomal length (as measured from the anterior margin of pronotum to the posterior margin of propodeum in profile) 1.12 mm (1.12); hind femur length (maximum length of hind femur) 0.50 mm (0.49); hind femur index (hind femur length/head width) 91 (89). Worker description. Head long, almost rectangular, with slightly convex lateral margins and almost straight posterior margin in full-face view; in profile flattened dorsoventrally. Median part of clypeus with anterior margin weakly and broadly concave. Mandible slender, strongly curved at the apical end of trulleum (this can be clearly observed when the mandibles are opened); basal two-thirds almost parallel-sided in outer view (Fig. 5), with long but bluntly tapered apical tooth followed by a trapezoidal lobe (probably fusion of two preapical teeth: “mtl” in Fig. 3) and three inconspicuous teeth. Antennal scape (segment I) flattened dorsoventrally, narrowed toward base; segment II bead-like, in frontal view strongly narrowed at base (“as-II” in Fig. 2); segment III slightly longer than broad and narrowed basally; segments IV and V almost as long as broad; segments VI–XI broader than long; apical segment longer than broad and bluntly pointed at apex. Pronotum longer than broad in dorsal view, with slightly convex dorsal face that merges into lateral face roundly; anterior slope short and steep. Remaining portion of mesosoma slightly narrower than pronotum and almost parallel-sided in dorsal view; nota and pleura roundly continuous; mesopleuron separated from metapleuron by a sulcus; lower portion of metapleuron defined posteriorly by a narrow furrow; propodeum with rather flat dorsum and steep posterior face. Femur and tibia of fore leg broader than those of mid- and hind legs; relatively broad gap present between mid- and hind coxae. Petiole seen from above much longer than broad, slightly narrowed posteriad, and laterally weakly convex, in profile much longer than high, weakly converging posteriad. Gaster with a long and up-curved sting. Whole body only weakly sculptured and moderately shining; mandible with sparse large punctures which generally bear setae; dorsum of head superficially punctate; clypeus with posterior portion almost unsculptured and shining; mesosoma more weakly sculptured than dorsum of head, with posteroventral portion of its side irregularly sculptured; petiole and gaster almost smooth and shining. Head with dense short hairs that are erect or suberect; mandible when closed with lower margin bearing relatively long and sparse standing hairs; antennal scape with sparse erect hairs in addition to denser short pubescence; hairs on funiculus generally short, especially on apical segments; mesosoma and petiole dorsally with sparser standing hairs; erect hairs on tibiae and tarsi shorter than those on femora; gastral terga dorsally with standing hairs that are denser than those on mesosoma; gastral sterna each with isolated erect hairs. Whole body light brown, with antennae and legs slightly yellowish. Etymology. The genus name Opamyrma is an anagram of Apomyrma for the first three letters. The specific name (hungvuong) derives from the legendary king Hung Vuong who founded the first Vietnamese state Van Lang.Published as part of Yamane, Seiki, Bui, Tuan Viet & Eguchi, Katsuyuki, 2008, Opamyrma hungvuong, a new genus and species of ant related to Apomyrma (Hymenoptera: Formicidae: Amblyoponinae), pp. 55-63 in Zootaxa 1767 on page 57, DOI: 10.5281/zenodo.27426
Parvimyrma Eguchi & Bui, 2007, gen. nov.
No full textParvimyrma gen. nov. Type-species. Parvimyrma sangi sp. nov. (Figs. 1–10) Worker diagnosis. Monomorphic myrmicine ants with the following combination of characteristics. Frontal lobe in full-face view only partially concealing the toruli, not extending posteriorly as a frontal carina; antennal scrobe absent; posteromedian portion of clypeus narrowly inserted between frontal lobes; median clypeal seta well developed; 1 st paracarinal seta well developed; lateral portions of clypeus not forming a raised rim or shield wall in front of the antennal insertions; the position of anterior tentorial pit as in Fig. 4; mandible triangular, overlapping but not crossing over at full closure, with 5 distinct teeth on the masticatory margin but without any tooth/denticles on the basal margin; trulleum open; hypostoma with a conspicuous lateral tooth just mesal to each mandibular base; anterior margin of labrum broadly concave medially; palpal formula: maxillary 2 and labial 2; antenna 11 -segmented, with a 2 -segmented club (Fig. 6); the apical antennal segment elongated much more than the preapical segment; eye completely absent. Promesonotum low, in profile almost flat or very weakly convex dorsally, without conspicuous humerus; promesonotal suture completely absent dorsally; mesosoma in dorsal view constricted between promesonotum and propodeum; metanotal groove relatively shallowly impressed dorsally; propodeum unarmed but with a narrow cuticular rim on each posterolateral corner of the dorsum; the rim running downward and connecting with metapleural lobe; each meso and metasternum without a conspicuous process; metapleural lobes low and round; propodeal spiracle small, situated a little behind the midlength of the sides of propodeum; metapleural gland large. Fore basitarsus with a long and thick seta on the posteroinner margin (sbt in Fig. 8); meso and metatibial spur absent. Petiole pedunculate anteriorly and with a distinct node; the peduncle with a small anteroventral process; postpetiole much shorter than petiole, in dorsal view a little broader than petiolar node, narrowly attached to the anteriormost end of gaster. Abdominal tergite IV (= gastral tergite I) broadly overlapping the sternite IV on the ventral surface of abdomen; gastral shoulder present (gs in Fig. 9); sting poorly developed (st in Fig. 9). Body smooth to very weakly sculptured. Notes. The characteristics highlighted above in italics are good grounds for placing Parvimyrma gen. nov. in the Solenopsis genus group (sensu Bolton, 2003). The morphology of Parvimyrma, however, disagrees with the other known genera belonging to the genus group as follows. 1) Allomerus — posteromedian portion of clypeus broadly inserted between frontal lobes; eye quite well developed; palpal formula (PF) 3, 2; antenna with a 3 -segmented club in which the proximal end of each segment forms a clear neck; promesonotum forming a dome (see Ettershank, 1966; Bolton, 1987). 2) Anillomyrma — masticatory margin of mandible with 3–4 teeth; mandibular blades crossing over at full closure; PF 2, 1; antenna 10 -segmented, with a 3 -segmented club; petiolar peduncle lacking an anteroventral process; postpetiole in dorsal view broadly attached to anterodorsal part of gaster; sting large (see Bolton, 1987). 3) Bondroitia — mandibular blades crossing over at full closure; antenna with a 3 -segmented club; metapleural gland small and inconspicuous; propodeal spiracle enormous, very close to margin of posterior face of propodeum; petiolar peduncle lacking an anteroventral process (see Bolton, 1987). 4) Carebarella — median portion of clypeus sharply defined by a pair of lateral carinae and forming a raised, oblong, flat region; masticatory margin of mandible with 4 teeth; PF 1, 2; eye present (but poorly developed); metanotal groove deeply impressed on the dorsum of mesosoma (see Ettershank, 1966; Bolton, 1987). 5) Diplomorium — median portion of clypeus not suddenly raised; posteromedian portion of clypeus broadly inserted between frontal lobes; antenna with a weakly differentiated club of 3 segments; eye present and conspicuous; promesonotum convex but not flat; postpetiole very narrowly attached to gaster; sting well developed (see Bolton, 1987). 6) Epelysidris — anterior clypeal margin with a pair of stout triangular teeth; basal margin of mandible with two broad-based bluntly triangular lobes; PF 3, 2; antenna 12 -segmented, with a strongly differentiated club consisting of 3 segments; eye present (but small); promesonotum strongly convex; sting long and strong (see Bolton, 1987). 7) Megalomyrmex — PF 4, 3 or 3, 2; antenna 12 -segmented, with a 3 -segmented club; eye well developed; metapleural lobes connected above by a distinct carina (see Ettershank, 1966; Bolton, 1987). 8) Monomorium — antennal club never of 2 segments; eye present (but reduced to a single ommatidium in the fossulatum -group) (see Bolton, 1987). 9) Nothidris — PF 4, 3; antenna 12 -segmented, with a 3 -segmented club; eye well developed (see Ettershank, 1966; Bolton, 1987). 10) Oxyepoecus — masticatory margin of mandible with 4 teeth; antenna with a 3 -segmented club; eye well developed; propodeum with a pair of sharp angles or dents (propodeal spine) (see Bolton, 1987). 11) Phacota — masticatory margin of mandible with 4 teeth; eye present. The diagnosis of the genus is poor because the single specimen of the genus (the holotype of the single member, Phacota sichelii) appears to have been lost or destroyed (see Bolton, 1987). 12) Solenopsis — masticatory margin of mandible at most with 4 teeth; antenna 9 - or 10 -segmented (see Ettershank, 1966; Bolton, 1987, 2003). FIGURES 1–3. Parvimyrma sangi, worker — 1, holotype (point-mounted), body in profile; 2, paratype (pointmounted), head in full-face view; 3, paratype (slide-mounted), anterior part of head in ventral view. labr, labrum (anterior margin); ms, median seta of clypeus; spp, subpetiolar process; ten, tentorium; tr, trulleum; 1 st pcs, 1 st paracarinal seta of clypeus. The general habitus of Parvimyrma is very similar to that of some members of Carebara. Because the concept of the genus Carebara was broadened by Fernández (2004), the presence of a median clypeal seta is the only characteristic separating Parvimyrma from Carebara. Fernández (2004) subdivided Carebara into three species complexes: C. concinna species complex (= Oligomyrmex sensu Ettershank, 1966), C. escherichi species complex (= Paedalgus sensu Bolton & Belshaw, 1993) and C. lignata species complex (= Carebara sensu Ettershank, 1966); and furthermore, he considered Afroxyidris, a monotypical genus established by Belshaw & Bolton (1994), to be highly apomorphic within Carebara. Below we provide characteristics of the three species complex and C. crigensis (= Afroxyidris crigensis) which disagree with the worker diagnosis of Parvimyrma. FIGURES 4, 5. Parvimyrma sangi, worker — 4, paratype (point-mounted), anterior part of head in anterodorsal view; 5, paratype (slide-mounted), mouthparts in ventral view. atp, anterior tentorial pit; lht, lateral hypostomal tooth; lp, labial palp; mp, maxillary palp; ms, median seta of clypeus; 1 st pcs, 1 st paracarinal seta of clypeus. 1) C. concinna species complex — worker dimorphic, major worker with massive head and mesosomal segmentation relatively well developed (see Ettershank, 1966; Fernández, 2004). 2) C. escherichi species complex — eye present (but reduced to 1–4 ommatidia); antenna 8 - or 9 -segmented; dorsum of propodeum very short, followed by a long steep posterior slope; sting strongly developed (see Ettershank, 1966; Bolton and Belshaw, 1993). 3) C. lignata species complex — antenna 9 -segmented (see Ettershank, 1966; Fernández, 2004). 4) C. crigensis — Mandible with two apical teeth followed by a long oblique edentate margin and a smaller basal tooth; median portion of clypeus with a transverse step; antenna 10 -segmented, with a 2 -segmented club; sting well developed (see Belshaw & Bolton, 1994). We found one Indo-Chinese species (worker, queen and male) and one Indo-Malayan species (worker only) which agree well with the concept of the C. lignata species complex despite the two species showing a critical diagnostic charasteristic of the Solenopsis genus group, i.e., a developed median clypeal seta present. The two species should be determined as Solenopsis by following Bolton (1994), but they show a series of characteristics which is seen in the typical worker of C. lignata species complex: antenna 9 -segmented, with a 2 -segmented club; eye completely absent; the median portion of clypeus in profile roundly and strongly swollen; clypeal carina evanescent or absent; clypeal teeth completely absent; the masticatory margin of their mandible with the apical and two distinct subapical teeth which are followed by one to three much reduced teeth (5–6 teeth in total); promesonotum in profile rather flat dorsally; in alates radial cell completely closed (see Ettershank, 1966; Bolton, 2003). Fernández (2004) examined a Carebara anophthalma worker from Ecuador having a developed median clypeal seta, but he concluded that it is a local variation (C. anophthalma is a member of the Carebara lignata species complex). Furthermore, recent molecular phylogenetic studies of ants (Moreau et al., 2006; Brady et al., 2006) do not support the monophyly of the tribe Solenopsidini and the Solenopsis genus group. These facts mean that the presence or absence of a median clypeal seta has been over-weighted in the classification of myrmicine ants. Because “lumping genera” seems to be a trend, it may be inevitable that Carebara, Solenopsis and their neighboring taxa (including Parvimyrma) will be combined into a single genus which may be too large and too heterogeneous. However, for the present, our opinions are as follows: 1) the proposition of Parvimyrma under the Solenopsis genus group is valid; 2) the two “ Carebara -like” species are tentatively treated as undetermined species of the genus Solenopsis (a comprehensive revision of Old World species of Carebara lignata species complex is needed); 3) Parvimyrma is distinguished from Solenopsis, the morphologically closest genus, by its 11 -segmented antenna and its triangular mandible with 5 distinct teeth on the masticatory margin; 4) the concept of the tribe Solenopsidini and the delimitation between its two genus groups are preserved because of its large practical value for descriptive taxonomy. Parvimyrma is easily distinguished from the other myrmicine genera known from the Indo-Chinese subregion by a combination of the following features: median clypeal seta well developed; posteromedian portion of clypeus narrowly inserted between frontal lobes; masticatory margin of mandible with 5 distinct teeth; antenna 11 -segmented, with a 2 -segmented club; eye completely absent.Published as part of Eguchi, Katsuyuki & Bui, Tuan Viet, 2007, Parvimyrma gen. nov. belonging to the Solenopsis genus group from Vietnam (Hymenoptera: Formicidae: Myrmicinae: Solenopsidini), pp. 39-47 in Zootaxa 1461 on pages 40-44, DOI: 10.5281/zenodo.27373
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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