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A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region
No full textBihn, Jochen H., Verhaagh, Manfred (2007): A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region. Zootaxa 1642: 1-12, DOI: 10.5281/zenodo.27396
FIGURES 7–9 in A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region
No full textFIGURES 7–9. Mystrium maren (holotype, worker): 7—head, frontal view, 8—dorsal view, 9—lateral view.Published as part of Bihn, Jochen H. & Verhaagh, Manfred, 2007, A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region, pp. 1-12 in Zootaxa 1642 on page 8, DOI: 10.5281/zenodo.27396
Myrmecovory in Neotropical primates
No full textAbstract Ants are the dominant group of animals in many habitats, particularly in tropical rainforests. High abundance and formation of large colonies convert them into a potential food source for a broad spectrum of animals. In this paper we review myrmecovory (consumption of ants) in Neotropical primates. Myrmecovory has been reported from 57 taxa (species + subspecies) out of 217 species of Neotropical primates, representing 18 out of 22 genera. The proportion of ants in the animal portion of the diet is highest amongst members of the genera Cebus , Sapajus , Cheracebus and Plecturocebus , but generally low in callitrichids, large pitheciids ( Cacajao , Chiropotes ) and atelids. Ants from seven subfamilies of Formicidae (out of 13 subfamilies found in the Neotropics) are consumed, including taxa with and without functional sting and with varying other defences. Foraging technics employed in myrmecovory range from picking ants from open substrates to extractive foraging involving the destruction of ant nests or shelters, but tool use has not been reported. We conclude that myrmecovory is widespread amongst Neotropical primates but on average contributes only a minor proportion of the diet. The diversity of foraging technics employed and lack of tool use in Neotropical primate myrmecovory, even for ants with functional stings and aggressive biting, suggests that tool use for myrmecovory in hominids has not evolved in response to ant defences but is a consequence of enhanced cognitive skills that evolved under other selection pressures.Abstract Ants are the dominant group of animals in many habitats, particularly in tropical rainforests. High abundance and formation of large colonies convert them into a potential food source for a broad spectrum of animals. In this paper we review myrmecovory (consumption of ants) in Neotropical primates. Myrmecovory has been reported from 57 taxa (species + subspecies) out of 217 species of Neotropical primates, representing 18 out of 22 genera. The proportion of ants in the animal portion of the diet is highest amongst members of the genera Cebus , Sapajus , Cheracebus and Plecturocebus , but generally low in callitrichids, large pitheciids ( Cacajao , Chiropotes ) and atelids. Ants from seven subfamilies of Formicidae (out of 13 subfamilies found in the Neotropics) are consumed, including taxa with and without functional sting and with varying other defences. Foraging technics employed in myrmecovory range from picking ants from open substrates to extractive foraging involving the destruction of ant nests or shelters, but tool use has not been reported. We conclude that myrmecovory is widespread amongst Neotropical primates but on average contributes only a minor proportion of the diet. The diversity of foraging technics employed and lack of tool use in Neotropical primate myrmecovory, even for ants with functional stings and aggressive biting, suggests that tool use for myrmecovory in hominids has not evolved in response to ant defences but is a consequence of enhanced cognitive skills that evolved under other selection pressures
Mystrium maren Bihn & Verhaagh, new species
No full textMystrium maren Bihn & Verhaagh, new species Fig. 7 –9, 12, 15 Type material. HOLOTYPE: Worker. INDONESIA: West Papua Province, Waigeo Island, near Urbinasopen, Gunung Susu, 0° 22 ' 45 '' S, 131 ° 15 ' 10 '' E, 350–450m a.s.l., January 2001 (leg. A. Riedel), deposited at MZB. PARATYPE: worker from the same collection as holotype, deposited at SMNK. Measurements and indices. Holotype worker: HL 2.46, HW 2.72, CI 111, SL 1.84, SI 68, ML 2,81, WL 2.73, PW 1.37; Paratype worker: HL 2.34, HW 2.64, CI 113, SL 1.71, SI 65, ML 2.81, WL 2.62, PW 1.35. Diagnosis (worker). The following character combination differentiates M. maren from all its congeners: the outer and inner margins of mandibles in dorsal view parallel and sinuate; the apex of each mandible only slightly expanded and subtruncate; outer face of labrum with a bilateral-symmetric rugoreticulum; maxillary palps 4 -segmented; the second segment of the maxillary palp longer than the basal (first) segment; antennal segment III at least twice as long as broad; each anterolateral corner of the head produced into a long and pointed spine; dorsum of head with rugose-reticulate cuticular sculpture and spatulate to clavate hairs; minute compound eyes. Description (worker). General morphology of the worker as shown in figures 7–9. Head wider than long; posterior margin of head in full-face view deeply and roundly emarginate. Each anterolateral corner of the head produced into a forward directed, long and curved spine. Mandibles long and slender; the outer and inner margins of each mandible in dorsal view parallel and distinctly sinuate; the inner margin with two staggered, longitudinal rows of hamulus-like teeth, each row with 12–14 teeth; teeth of the lower row larger than those of the upper row; the apex of each mandible only slightly expanded and subtruncate; the medioventral corner of the apex with an additional tooth; distal 2 / 3 on the dorsal face and distal half on the ventral face of each mandible with a longitudinal carina. Labrum (fig. 15) about twice as wide as long; its distal margin convex with a median emargination; outer (ventral) face of labrum entirely foveolate-reticulate, and overlaid by a peculiar pattern of rugae: one ruga running between basolateral corners in an arc which is parallel to the distal margin and divides the outer surface of the labrum into distal and basal areas; additional rugae delimiting symmetrically two roughly rectangular fields on the median portion of the distal area. Maxillary palps 4 -segmented (fig. 12); the basal (first) segment roughly cone-shaped, shorter and much broader than the second. Labial palps 3 -segmented. Anterior clypeal margin convex with 9 truncated teeth; the teeth evenly spaced along the clypeal margin, without a median toothless gap. Antennal scape (antennal segment I) in dorsal view (as in fig. 7) curved only weakly and broadened in its distal part, in frontal view (perpendicular to dorsal view) strongly curved, with its predistal part ventrally broadened; apex of scape bends only weakly dorsad in this view. Each of antennal segments II–VI longer than broad; antennal segment III at least twice as long as broad; antennal segments IX–XII (the four distal segments) forming a weak club. Compound eyes minute, consisting of 7–10 ommatidia, situated near the midpoint of the sides of the head. In lateral view, the dorsal outline of the mesosoma almost flat; promesonotal suture wide and deeply depressed; metanotal groove distinct but shallower and narrower than promesonotal suture. Mesosoma in dorsal view distinctly constricted between pronotum and propodeum. Propodeal spiracle directed laterad. Hind tarsus, when five tarsal segments combined, only slightly longer than hind tibia. Petiolar node in dorsal view about twice as broad as long. Subpetiolar process expanded anteroventrally and forming a rounded apex. Gastral segment I in dorsal view less than twice as broad as long, nearly as broad as the segment II. Head and dorsa of mesosoma, petiolar node and gastral segment I rugose-reticulate; anterodorsal part of head between scape insertion and lateral spine with longitudinal rugae; lateral face of each mandible with evenly spaced, oblique rugae; coxae with strong rugae; dorsa of gastral segments I and II with longitudinal rugae, which are sparsely interconnected by transverse ridges; rugae finer on gastral segment II than on I; helcium and girdling constriction of gastral segment II scrobiculate; intervals between rugae with fine foveolatereticulate microsculpture; strength of microsculpture varies greatly among body parts: distinct on anterodorsal and mediodorsal faces of head, on lateral faces of mesosoma, in promesonotal depression, on posterior face of propodeum, on anterior face of petiole, on all gastral segments including the presclerites and on legs; microsculpture on posteriodorsal and ventral faces of head, and on dorsa of mesosoma and petiolar node very shallow and obscure, i.e. the areas nearly smooth (the less-microsculptured areas were mostly hidden under soil particles, that stuck on the integument [or possibly a mixture of soil particles and integumental secretion], and became visible only after cleaning). Dorsum of head, antennal scape, antennal segments II–VII, mesosoma, petiole and dorsum of gaster with decumbent to suberect, bluntly pointed, narrowly spatulate or clavate setae; posterodorsal margin of gastral segments I–IV with a row of subdecumbent, longer and narrower spatulate setae; pygidium with both spatulate and simple hairs; setae on ventrum of head appressed and simple; hairs on ventrum of gaster subdecumbent and simple; antennal segment IX–XII densely covered with decumbent, simple hairs and a few simple, erect hairs. Most body parts dark brown to black, except for anterior part of head, mandibles, antennae and gaster which are of a variable lighter, rusty brown color; coloration of legs changing gradually from dark brown coxae to yellow brown apical tarsal segments; integument mostly dull, but the less-microsculptured areas somewhat shining. Queen and male unknown. Etymology. Named in dedication to Dr. Maren Scheidhauer, friend of the first author and as beautiful — though of low overall resemblance — as this ant. The specific name is an arbitrary combination, to be treated as a noun in apposition. Distribution. The two known specimens were extracted from a leaf litter sample taken in an old growth rainforest near the summit of Gunung Susu. Comments. As in M. leonie we cannot determine which reproductive strategy M. maren follows. But we conclude that the described specimen is a worker because wingless reproductives in Mystrium have reduced mandibles which are inappropriate for hunting. This is clearly not the case for the holotype of M. maren. The holotype and paratype of M. maren show similar camouflage tendencies as described for M. leonie.Published as part of Bihn, Jochen H. & Verhaagh, Manfred, 2007, A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region, pp. 1-12 in Zootaxa 1642 on pages 7-11, DOI: 10.5281/zenodo.27396
Mystrium camillae Emery
No full text<i>Mystrium camillae</i> Emery <p>Fig. 1–3, 10, 13</p> <p> <i>Mystrium Camillae</i> [sic] Emery, 1889: 491, pl. 10, figs. 1–3. Syntype worker and queen: Myanmar (as “ Birmania ”: Bhamò (Fea) [MCSN] (not examined; photographs of syntype worker and queen examined on AntWeb (www.antweb.org): CASENT0102123 (worker), CASENT0102124 (queen)).</p> <p> <i>Mystrium camillae</i> Emery subsp. <i>javana</i> Karawaiew, 1925: 73, figs. 1 & 2. Syntype worker: Java, limestone mountain near Tjampea, no. 2389, 2 workers on the ground, under leaves (Karawaiew) (not examined). Synonymy by Brown, 1960: 170.</p> <p> <i>Mystrium camillae</i>; Menozzi, 1929: 535 –536, fig. 9. Revision of the genus and key to species.</p> <p> <i>Mystrium oculatum</i> Xu, 1998: 161, figs. 1 & 2. Holotype worker: China: Yunnan Province, Mengla County, Menglun Town, Bakaxiaozhai (Xu Zheng-hui) [SWFC] (not examined; photographs of paratype examined on AntWeb (www.antweb.org): CASENT0104982 (worker)). <b>New synonymy</b>.</p> <p> <b>Material examined.</b> Indonesia: Sumatra: Lampung, Tulang Bawang, Gn. Tanggang, 05°43.933' S, 105°06.598' E, 580m (1 worker, 9.VIII.2006, A. Riedel) [SMNK]; Sumatra: Lampung, Tulang Bawang, Gn. Tanggang, 05°43.938' S, 105°06.440' E, 580m (5 workers, 9.VIII.2006, A. Riedel) [SMNK]; Java: Jawa Barat, Ciamis, Gn. Sawal, Batu Cakra, 07°14'55'' S, 108°15'46'' E, 990m (1 worker, 1.X.2005, A. Riedel) [SMNK]. MALAYSIA (WEST): Negri Sembilan, Simpang Pertang, Pasoh Forest Reserve, 02°59' N, 102°19' E (1 worker, 29.III.1992, K. Rościszewski) [SMNK]; MALAYSIA (WEST): Terengganu, Lake Kenyir, 04°58' N, 102°49' E, 300–400m (22 workers, 7.–12.VII.2001, A. Schulz) [SMNK].</p> <p> <b>Measurements and indices.</b> Workers: HL 0.81–1.75, HW 0.85–1.64, CI 88–105, SL 0.50–1.00, SI 54– 64, ML 0.52–1.75, WL 0.91–1.49, PW 0.47–0.80 (n = 31).</p> <p> <b>Diagnosis (worker).</b> The following character combination differentiates <i>M. camillae</i> from all its congeners in the Indo-Australian region: the apex of each mandible distinctly expanded and rounded in lateral view, with a more or less triangular and caudally directed tip on the inner side; outer face of labrum entirely covered with a weakly developed, irregular rugoreticulum; maxillary palps 4-segmented; the second segment of the maxillary palp shorter than the basal (first) segment and less than half as broad as the basal segment; antennal segment III shorter than twice its width; each anterolateral corner of the head produced into a short, nearly triangular, pointed spine; dorsum of head with rugose-reticulate cuticular sculpture and spatulate hairs; minute compound eyes; petiolar node not broader than twice its length measured in dorsal view.</p> <p> <b>Distribution.</b> Widely distributed in the Indo-Australian region and neighboring countries. Recorded from Australia, Brunei, China, India, Indonesia, Malaysia, Myanmar, Papua New Guinea, the Philippines and Singapore.</p> <p> <b>Comments.</b> Brown (1960, p. 170) gave no justification for the synonymy of <i>M. camillae</i> subsp. <i>javana</i> under <i>M</i>. <i>camillae</i> but the differences between the taxa given in the description of Karawaiew (1925) fall within the variation of the senior synonym. The most important difference between the taxa — the shape of the mandible apex — depends on the angle from which the mandible is viewed. The triangular tip is highly variable in the specimens examined and often worn out. The number of truncated teeth at the anterior clypeal margin varies from 6–7 in the specimens we have seen and thus is not a character to distinguish the taxa. In most cases there is a toothless gap between the left and right group of these teeth (but see the specimens from Northern Australia depicted on AntWeb [CASENT0172841, CASENT0172082]. From Karawaiew’s description it is clear that he never had a specimen of <i>M. camillae</i> at hand but made his judgment of the species just from the description and the drawings of Emery (1889).</p> <p> Xu (1998: 161, figs. 1 & 2) notes in his description of <i>M. oculatum</i> that this species is close to <i>M. camillae</i> but differs from it by: “small eyes present; central dorsum of hat flat; metanotal groove only shallowly depressed; declivity of propodeum flat, not depressed; anterodorsal angle of petiolar node more extruding.” All examined specimens of <i>M. camillae</i> possess minute compound eyes. The presence of eyes was already noted in the original description of <i>M. camillae</i> by Emery (1889) and again in Menozzi’s revision. Therefore, the presence of eyes in <i>M. oculatum</i> cannot be regarded as a diagnostic character to distinguish it from <i>M. camillae</i>. All other diagnostic characters given for <i>M. oculatum</i> by Xu vary much among individuals of <i>M. camillae</i>. The morphology of <i>M. oculatum</i> as described by Xu (1998: 161–162, figs. 1 & 2) and shown by photographs of a paratype of <i>M. oculatum</i> on AntWeb (www.antweb.org: CASENT0104982) falls well within the range of morphological variation exhibited by the examined specimens of <i>M. camillae</i>. Additionally, all but one metric character of <i>M. oculatum</i> fall into the range of <i>M. camillae</i>. The exception is CI, which is slightly higher.</p>Published as part of <i>Bihn, Jochen H. & Verhaagh, Manfred, 2007, A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region, pp. 1-12 in Zootaxa 1642</i> on pages 2-3, DOI: <a href="http://zenodo.org/record/273961">10.5281/zenodo.273961</a>
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Mystrium leonie Bihn & Verhaagh, new species
No full text<i>Mystrium leonie</i> Bihn & Verhaagh, new species <p>Fig. 4–6, 11, 14</p> <p> <b>Type material.</b> HOLOTYPE: Worker. INDONESIA: Papua Province, Jayawijaya, near Elelim, 03°49' S, 139°24' E, 750m a.s.l., December 2004 (leg. A. Riedel), deposited at MZB.</p> <p> <b>Measurements and indices.</b> Holotype worker: HL 2.26, HW 2.45, CI 108, SL 1.63, SI 66, ML 2.80, WL 2.50, PW 1.18.</p> <p> <b>Diagnosis (worker).</b> The following character combination differentiates <i>M. leonie</i> from all its congeners: the apex of each mandible only slightly expanded and subtruncate; outer face of labrum with an irregular rugoreticulum; maxillary palps 3-segmented; the second segment of the maxillary palp longer than the basal (first) and third segment, respectively; antennal segment III at least twice as long as broad; antennal scape broadened in its distal part, this part ventrally tapering into a lamella; each anterolateral corner of the head produced into a long and pointed spine; dorsum of head with rugose-reticulate cuticular sculpture and clavate hairs; minute compound eyes.</p> <p> <b>Description (worker).</b> General morphology of worker as shown in figures 4–6. Head wider than long; posterior margin of head in full-face view deeply and roundly emarginate. Each anterolateral corner of head produced into a forward directed, long and curved spine. Mandibles long and slender, basal 2/3 straight, distal 1/3 incurved; the inner margin with two staggered, longitudinal rows of hamulus-like teeth, each row with 14 teeth; the teeth of the lower row larger than those of the upper row; the apex of each mandible only slightly expanded and subtruncate; the medioventral corner of the apex with an additional tooth; distal 3/4 on dorsal side and distal half on ventral side of each mandible with a longitudinal carina.</p> <p>Labrum (fig. 14) about twice as wide as long; its distal margin convex with a median, broad emargination; outer (ventral) face of labrum entirely foveolate-reticulate, and partly overlaid by an irregular rugoreticulum; this rugoreticulum is restricted to the distal half of the outer face of the labrum.</p> <p>Maxillary palps 3-segmented (fig. 11); the second segment longer than the basal (first) and the distal (third) segment; basal (first) segment cylindrical, its diameter only slightly larger than the diameter of the second segment. Labial palps 3-segmented.</p> <p>Anterior clypeal margin convex with 8 truncated teeth; the teeth evenly spaced along the clypeal margin, without a median toothless gap. Antennal scape (antennal segment I) in dorsal view (as in fig. 4) curved only weakly in its distal part, distal part broadened; in frontal view (perpendicular to dorsal view) scape evenly curved with its predistal part broadened ventrally, tapering into a lamella, apex of scape bends dorsad thus forming a concavity on the dorsal side of the scape. Each of antennal segments II–VIII longer than broad; antennal segment III at least twice as long as broad; antennal segments IX–XII (the four distal segments) forming a weak club. Compound eyes minute, consisting of 7–10 ommatidia, situated near the midpoint of the sides of the head.</p> <p>In lateral view, the dorsal outline of the mesosoma almost flat; promesonotal suture wide and deeply depressed, metanotal groove indistinct. Mesosoma in dorsal view distinctly constricted between pronotum and propodeum. Propodeal spiracle directed laterocaudad. Hind tarsus, when five tarsal segments combined, only slightly longer than hind tibia. Petiolar node in dorsal view more than twice as broad as long. Subpetiolar process expanded anteroventrally and forming a rounded apex. Gastral segment I less than twice as broad as long, nearly as broad as segment II.</p> <p>Head and posterior face of propodeum, dorsa of mesosoma, petiolar node and gastral segment I rugosereticulate; anterodorsal part of head between scape insertion and lateral spine with longitudinal rugae; outer face of each mandible with evenly spaced, oblique rugae; distal part of antennal scape with strong rugae; coxae with strong rugae; dorsa of gastral segments I and II with longitudinal rugae, which are sparsely interconnected by transverse ridges; rugae finer on gastral segment II than on segment I; helcium and girdling constriction of gastral segment II scrobiculate. Intervals between rugae with fine foveolate-reticulate microsculpture; strength of microsculpture varies greatly among body parts: distinct on anterodorsal and mediodorsal faces of head, on lateral faces of mesosoma, in promesonotal depression, on posterior face of propodeum, on anterior face of petiole, on all gastral segments including the presclerites and on legs; microsculpture on posterodorsal and ventral faces of head, and on dorsa of mesosoma and petiolar node very shallow and obscure, i.e. these areas nearly smooth (the less-microsculptured areas were mostly hidden under soil particles, that stuck on the integument [or possibly a mixture of soil particles and integumental secretion], and became visible only after cleaning).</p> <p>Dorsum of head, antennal scape, antennal segments II–VIII, mesosoma, petiole and dorsum of gaster with decumbent to suberect, bluntly pointed, clavate setae; posterodorsal margin of gastral segments I–IV with a row of subdecumbent, longer and narrower clavate setae; pygidium with both clavate and simple hairs; setae on ventral face of head appressed and simple; hairs on ventrum of gaster subdecumbent and simple; antennal segments IX–XII densely covered with decumbent, simple hairs and a few simple, erect hairs.</p> <p>Most body parts dark brown to black, except for anterior part of head, mandibles, antennae and gaster which are of a variable lighter, rusty brown color; coloration of legs changing gradually from black coxae to yellow brown distal tarsal segments; integument mostly dull, but the less-microsculptured areas somewhat shining.</p> <p>Queen and male unknown.</p> <p> <b>Etymology.</b> Named in dedication to Leonie Geeltje Aimée Wiegel, the daughter of M. Verhaagh, being as unique as this species known from a single specimen. The specific epithet is to be treated as a noun in apposition.</p> <p> <b>Distribution.</b> The single known specimen was extracted from a leaf litter sample taken in an old growth rainforest near Elelim.</p> <p> <b>Comments.</b> Species of the genus <i>Mystrium</i> in Madagascar show two distinct reproductive strategies and relevant colony structures (Molet <i>et al.</i> 2006). In some species (e.g. <i>M. rogeri</i> Forel 1899) each colony has a single dealate queen with a larger thorax than workers but with mandibles similar to those of the workers. In colonies of other species (e.g. “ <i>M.`red</i> `” in Molet <i>et al.</i> 2006) winged queens are missing and half of the female adults belong to wingless reproductives which are smaller and allometrically distinct from workers. Because of the lack of nest series we cannot know the reproductive strategy adopted by <i>M. leonie</i>. But we can eliminate the possibility that the described specimen of <i>M. leonie</i> is not a worker but a wingless reproductive because wingless reproductives in <i>Mystrium</i> have reduced mandibles which are inappropriate for hunting. The holotype of <i>M. leonie</i> has well-developed mandibles.</p> <p>Much of the holotype specimen, and especially the dorsum, is covered with a tightly adhering layer that is presumably soil and/or detritus. This layer in combination with the overall cryptic behavior probably acts as a camouflage for foragers in the leaf litter.</p>Published as part of <i>Bihn, Jochen H. & Verhaagh, Manfred, 2007, A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region, pp. 1-12 in Zootaxa 1642</i> on pages 5-7, DOI: <a href="http://zenodo.org/record/273961">10.5281/zenodo.273961</a>
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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