Modality effects in vocabulary acquisition

It is unknown whether modality affects the efficiency with which humans learn novel word forms and their meanings, with previous studies reporting both written and auditory advantages. The current study implements controls whose absence in previous work likely offers explanation for such contradictory findings. In two novel word learning experiments, participants were trained and tested on pseudoword - novel object pairs, with controls on: modality of test, modality of meaning, duration of exposure and transparency of word form. In both experiments word forms were presented in either their written or spoken form, each paired with a pictorial meaning (novel object). Following a 20-minute filler task, participants were tested on their ability to identify the picture-word form pairs on which they were trained. A between subjects design generated four participant groups per experiment 1) written training, written test; 2) written training, spoken test; 3) spoken training, written test; 4) spoken training, spoken test. In Experiment 1 the written stimulus was presented for a time period equal to the duration of the spoken form. Results showed that when the duration of exposure was equal, participants displayed a written training benefit. Given words can be read faster than the time taken for the spoken form to unfold, in Experiment 2 the written form was presented for 300 ms, sufficient time to read the word yet 65% shorter than the duration of the spoken form. No modality effect was observed under these conditions, when exposure to the word form was equivalent. These results demonstrate, at least for proficient readers, that when exposure to the word form is controlled across modalities the efficiency with which word form-meaning associations are learnt does not differ. Our results therefore suggest that, although we typically begin as aural-only word learners, we ultimately converge on developing learning mechanisms that learn equally efficiently from both written and spoken materials

Expanded concept and revised taxonomy of the milliped family Xystodesmidae Cook, 1895 (Polydesmida: Leptodesmidea: Xystodesmoidea): incorporations of Euryuridae Pocock, 1909 and Eurymerodesmidae Causey, 1951, taxon revivals/proposals/transferrals, and a distributional update

Euryuridae Pocock 1909 and Eurymerodesmidae Causey 1951, both endemic to the eastern/central United States (US), are incorporated into Xystodesmidae Cook 1895 and reduced to subfamilies and (sub)tribes n. stats. Euryurina and Melaphina Brolemann 1916, n. stats., are sister-taxa that differ primarily in epiproctal configurations and comprise Euryurini; sister-taxa Eurymerodesmina and Nannariina Hoffman 1964, n. stats., the latter transferred from Xystodesminae, comprise Eurymerodesmini, n. stat., in which plesiomorphic forms exhibit sublinear, “stick-like,” and subapically curved/bent gonopodal acropodites with moderately-long to long hairs, often with distal tufts, on their “inner” surfaces. Additional transferrals include Wamokia Chamberlin from the xystodesmine tribe Xystocheirini to Xystodesmini (= Harpaphini), and Macellolophus Attems, from Xystodesmidae to Chelodesmidae. Except for Chonaphini, the term, “prefemoral process,” has traditionally been assigned to the secondary and shorter telopodital projection regardless of its position, origin, or configuration. Homology of these different structures has never been demonstrated and requires investigation, but the multitude of differences suggests that they are not such and warrant different names, for example “femoral process,” for the similarly positioned branches in Devillea Brölemann and Rhysodesmus Cook (Xystodesminae: Devilleini, Rhysodesmini). The latter tribe may be polyphyletic, and new tribes may be required for components with acicular “prefemoral processes” (Boraria and Cherokia, both by Chamberlin, Gyalostethus and Erdelyia, both by Hoffman, and Pleuroloma Rafinesque) and the southeastern US genera with small-bodied species (Caralinda Hoffman and Gonoessa, Parvulodesmus, and Lourdesia, all by Shelley). Taxonomic value is accorded the “prefemoral extension/elongation,” which is absent from Eurymerodesmina; complete, encircles the acropodite, and extends for ~1/3 to 1/2 of the latter’s lengths in Euryurini; and incomplete and extends for ~1/4 to 1/3 of the “outer” acropodital surfaces in Nannariina and xystodesmine tribes. Other newly recognized taxonomic characters include the “inner” and “outer” acropodital surfaces/margins, the position on the acropodital stem of the “distal curve/bend,” and the length of the “distal zone.” Rhysodesmus and Sigmoria (Rudiloria) t. trimaculata (Wood) (Xystodesminae: Rhysodesmini, Apheloriini) are recorded from, respectively, Chihuahua, Mexico, and Québec, Canada, as are Xystodesmidae/-inae and, provisionally, Chonaphini, Montaphe Chamberlin, and M. elrodi(Chamberlin), the only plausible taxa for an unidentifiable juvenile from near Yahk and only 2.5 km (1.6 mi) north of the International Border. The southern periphery of interior British Columbia (BC) thus represents the second xystodesmid faunal region in BC and the third in Canada. While incorporation of Euryuridae does not affect the family’s overall distribution, that of Eurymerodesmidae fundamentally alters it by joining the formerly separate East-Nearctic and Meso-American regions into a continuous one extending, north-south, from Montréal Island, Québec, to Santa Ana Department, El Salvador, a distance of around 4,944 km (3,090 mi). Xystodesmidae also inhabit two West-Nearctic regions, one in the interior stretching from southernmost BC to northeastern Oregon and the other running along the Pacific Coast from southern Alaska to southern California. The family also occupies two Palearctic regions, each with three subregions, an eastern one spreading from Hokkaido, Japan, and the southern Maritime Province, Russia, to Taiwan; a point locality in northern Vietnam; and southern/eastern China. The second Palearctic area extends along the Mediterranean and adjoining seas from Morocco, Sardinia, and the southeastern corner of France to Cyprus and southern coastal Turkey. New locality data, references, and maps are provided along with diagnostic accounts of all reconceptualized taxa and new/revived statuses. A simple, sublinear, “stick-like” acropodite with a curve or bend near midlength or subapically and without a secondary telopodital projection is the hypothesized plesiomorphic gonopodal condition in Xystodesmidae. This form has undergone multitudinous modifications/alterations – twists, curls, variably configured thickened and laminate expansions, reductions, bi-/trifurcations, enlargements, ornamentations, etc. that are manifested in today’s xystodesmine tribes. When Avalonia collided with Baltica 450 million years ago, ancestral xystodesmoideans on the former dispersed into the latter, penetrated and occupied vacant niches, and evolved into today’s Melaphina (Euryurinae: Euryurini) and Devilleina (Xystodesminae). A similar evolutionary burst leading to today’s Nearctic and East-Palearctic faunas occurred 10 million years later when Avalonia + Baltica collided with Laurentia to form Euramerica. Ancestral forms of Euryurinae and Xystodesminae again penetrated vacant niches and evolved; the former maintained the general gonopodal structural pattern of Melaphina but changed the epiproct from triangular to broad and spatulate, thereby creating Euryurina. The earliest xystodesmine taxa to evolve in Laurentia were Rhysodesmini and Rhysodesmus, which spread southwestward, penetrated “proto- Mexico, and left relict populations in today’s southern Appalachians. Eurymerodesmina and Nannariina arose from ancestral euryurine stock prior to the Cretaceous in western Appalachia in their present area of overlap. The former dispersed to the west and south while the latter expanded to the east and north; consequently, the Western Inland Seaway minimally impacted Nannariina while eradicating Eurymerodesmina from the inundated area. Today’s populations in the Plains and south-southeastern states therefore represent secondary dispersion in the past 50-60 million years. The Seaway also eradicated Rhysodesmus from these areas, but enough forms survived in high mountain refugia to replenish the fauna when the embayment receded

The enigmatic milliped genus \u3ci\u3ePandirodesmus\u3c/i\u3e Silvestri 1932 and description of a new species from Tobago represented by males (Polydesmida: Leptodesmidea: Chelodesmidae: Chelodesminae: Pandirodesmini)

Pandirodesmus rutherfordi, n. sp., represented by 18 individuals including eight adult males, occurs in secondary forests near Charlotteville and Speyside, Tobago, Trinidad and Tobago. Along with the type and second species, P. disparipes Silvestri, from Guyana and known only from females, the segmental legs of P. rutherfordi alternate between long (anterior pairs) and short (posterior ones), spiracular openings are on straw-like tubules, and ozopores are located on paramedian metatergal spines. These features appear to be adaptations for biotopes of loose sand, detritus, or frass, and 17 specimens, including the six juveniles, exhibit coatings of “sand grains” that are loosely cemented together and to the smooth, translucent, grayish-white exoskeleton. The tubules and spines elevate the spiracles and ozopores above the coating, thereby ensuring that they remain open and functional. The coating, which provides camoufl age and lends strength and rigidity to the poorly sclerotized exoskeleton, is a subuniform “pavement” that covers the entire animal except the labrum/clypeus, tarsal and antennal apices, prozonae, paraprocts, and the gonopods in males. Ramose/dendritic setae, particularly on narrowly rounded podo-/ antennomeres, trap “sand grains,” and the ozopore secretions apparently constitute the “glue” that cements the coating, as evidenced circumstantially by layers of “sand” between the spines on the anterior metaterga, where they are physically closest. The alternating segmental leg lengths, in part due to differing ventrolateral and ventromedial origins, appear to be an adaptation for lateral/sideways motion in which the long (anterior) legs extend laterally and pull the body to the level of the short (posterior) ones, which continue the motion while the anterior legs extend to begin the next stroke. The opposing legs perform the complementary pushing motion a fraction after the long legs initiate the pulling stroke and hence are slightly and purposefully out of sync. An adult male paratype lacks the coating, probably because it had just molted and lacked time to amass it; the juvenile female paratype of P. disparipes also is “naked,” as was, according to Silvestri, the now lost adult female holotype. Until fresh material is collected, coatings cannot be confi rmed for P. disparipes even though it shares the anatomical modifi cations that seem adaptions for such. The minute, triramous gonotelopodites of P. rutherfordi are unlike any known for a chelodesmid, so the current generic placement, in a monotypic tribe in the nominate chelodesmid subfamily, is retained. With species in both South America and the southern Antilles, Pandirodesmus/ini had to exist on both the “proto-Antillean” terrane and the adjoining part of Pangaean Gondwana before the former rifted in the Cretaceous/Paleocene, ~66 million years ago, and P. rutherfordi is a remnant of the former population that became isolated on present-day Tobago when the terrane fragmented. Affinity between Guyanan and southern Antillean platyrhacid millipeds (Polydesmida: Leptodesmidea) suggest that Pandirodesmus/ini may occur sporadically as far north in the island chain as St. Lucia

Parajulid milliped studies XII: Initial assessment of \u3ci\u3ePtyoiulus\u3c/i\u3e Cook 1895 and neotype designations for \u3ci\u3eJulus impressus\u3c/i\u3e Say 1821 and \u3ci\u3eJ. montanus\u3c/i\u3e Cope 1869 (Diplopoda: Julida)

Ptyoiulus Cook 1895, the dominant parajulid diplopod genus in the eastern United States (US), comprises two species – P. impressus (Say 1821), with a slanted, fl ared, circumferentially entire, and marginally serrate apical calyx on the anterior gonopod coxal process, and P. montanus (Cope 1869), n. comb., with a smooth, upright, cupulate calyx that is open caudad and coaxial with the process’ stem. The genus occupies a broad area between the Mississippi River and Atlantic Ocean extending from southern New England, Ontario, and Michigan to the Florida Panhandle and four small disjunct ones – from Montreal, Québec, to northern Vermont, along southwestern Lake Michigan in Wisconsin and Illinois; northeastern/eastcentral Arkansas, primarily in Crowley’s Ridge physiographic feature and beside the “bootheel” of Missouri; and a point locality in northeastern Louisiana just south of the Arkansas line. A male from Chester County (Co.), Pennsylvania, is designated as the neotype of Julus impressus, as is one from Durham Co., North Carolina, for J. montanus. As both species inhabit Montgomery Co., Virginia, the type locality of J. montanus, we exercise the right of fi rst reviser, conserve the latter name, and assign it to the species with the smooth, cupulate, and coaxial calyx. We also exercise fi rst reviser rights and assign Parajulus ectenes Bollman 1887 to this form, thereby relegating it to synonymy under Ptyoiulus montanus. Other new synonymies include Ptyoiulus georgiensis Chamberlin 1943 under P. impressus and P. coveanus Chamberlin 1943 under P. montanus. Both Ptyoiulus and P. impressus are projected for Delaware and Rhode Island and newly reported from Québec, Connecticut, District of Columbia, Maryland, Mississippi, South Carolina, Vermont, West Virginia, and Wisconsin, and the genus and species, respectively, are newly documented from Louisiana and Arkansas; P. montanus is newly cited from Alabama, Arkansas, Georgia, Mississippi, and South Carolina. Ptyoiulus impressus occupies every state except perhaps Louisiana and is the only species in areas that were inundated during the Cretaceous and glaciated during the Pleistocene; by contrast, P. montanus inhabits a relatively narrow east/west transect through the center of the generic range. Their distribution patterns suggest an old species, montanus, being actively displaced by the younger and more successful impressus. The decurvature of the epiproct in uroblaniulinines appears to increase with age and developmental stage. A key is presented to parajulid familygroup taxa in the US and Canada east of the Rocky Mountains

Parajulid milliped studies XI: Initial assessment of the tribe Gosiulini (Diplopoda: Julida)

The parajulid milliped tribe Gosiulini (Diplopoda: Julida) comprises two genera – Gosiulus Chamberlin, with three projections on the posterior gonopod and two species in the southcentral/southwestern United States (US) [Arizona, Colorado, New Mexico, and Texas], and monotypic Minutissimiulus Shelley, n. gen., with two projections, in Nuevo León, Mexico. Gosiulus conformatus Chamberlin occupies the plains/fl atlands of Texas, while its congener inhabits high elevations to the west in all four US states. Both are anticipated in Mexico (Coahuila, Chihuahua, and Sonora), and G. conformatus is expected in southeastern Colorado, eastern New Mexico, and the Oklahoma panhandle. The eastern boundary of G. conformatus and the genus/tribe conforms to the western border of the Piney Woods biome in eastern Texas. As shown by the posterior gonopod drawing in the original description, Parajulus timpius Chamberlin, previously considered of “uncertain generic position or validity,” is unquestionably the oldest name for the western species. The anteriormost posterior gonopod projection, absent from Minutissimiulus, is considered the “prefemoral process,” while the “solenomere” and a third branch arise from a common base. Because of positional homology with “process ‘C’” in Nesoressini, the last projection is accorded this name, which may also apply to the “prefemoral process” in Aniulini. Minutissimiulus biramus Shelley, n. sp., is proposed along with the following new subjective synonymies: Apacheiulus Loomis under Gosiulus; Ziniulus aethes and Z. medicolens, both by Chamberlin, and Z. ambiguus and Z. nati, both by Loomis, under G. conformatus; and A. pinalensis and A. guadelupensis, both by Loomis, under G. timpius, new combination. Ziniulus navajo Chamberlin becomes an objective synonym of P. timpius because its holotype is designated neotype of the latter. Minutissimiulus biramus Shelley is the fi rst Mexican gosiuline and “mainland” Mexican parajulid not in the tribe Parajulini

Parajulid milliped studies XI: Initial assessment of the tribe Gosiulini (Diplopoda: Julida)

The parajulid milliped tribe Gosiulini (Diplopoda: Julida) comprises two genera – Gosiulus Chamberlin, with three projections on the posterior gonopod and two species in the southcentral/southwestern United States (US) [Arizona, Colorado, New Mexico, and Texas], and monotypic Minutissimiulus Shelley, n. gen., with two projections, in Nuevo León, Mexico. Gosiulus conformatus Chamberlin occupies the plains/fl atlands of Texas, while its congener inhabits high elevations to the west in all four US states. Both are anticipated in Mexico (Coahuila, Chihuahua, and Sonora), and G. conformatus is expected in southeastern Colorado, eastern New Mexico, and the Oklahoma panhandle. The eastern boundary of G. conformatus and the genus/tribe conforms to the western border of the Piney Woods biome in eastern Texas. As shown by the posterior gonopod drawing in the original description, Parajulus timpius Chamberlin, previously considered of “uncertain generic position or validity,” is unquestionably the oldest name for the western species. The anteriormost posterior gonopod projection, absent from Minutissimiulus, is considered the “prefemoral process,” while the “solenomere” and a third branch arise from a common base. Because of positional homology with “process ‘C’” in Nesoressini, the last projection is accorded this name, which may also apply to the “prefemoral process” in Aniulini. Minutissimiulus biramus Shelley, n. sp., is proposed along with the following new subjective synonymies: Apacheiulus Loomis under Gosiulus; Ziniulus aethes and Z. medicolens, both by Chamberlin, and Z. ambiguus and Z. nati, both by Loomis, under G. conformatus; and A. pinalensis and A. guadelupensis, both by Loomis, under G. timpius, new combination. Ziniulus navajo Chamberlin becomes an objective synonym of P. timpius because its holotype is designated neotype of the latter. Minutissimiulus biramus Shelley is the fi rst Mexican gosiuline and “mainland” Mexican parajulid not in the tribe Parajulini

Expanded concept and revised taxonomy of the milliped family Xystodesmidae Cook, 1895 (Polydesmida: Leptodesmidea: Xystodesmoidea): incorporations of Euryuridae Pocock, 1909 and Eurymerodesmidae Causey, 1951, taxon revivals/proposals/transferrals, and a distributional update

Euryuridae Pocock 1909 and Eurymerodesmidae Causey 1951, both endemic to the eastern/central United States (US), are incorporated into Xystodesmidae Cook 1895 and reduced to subfamilies and (sub)tribes n. stats. Euryurina and Melaphina Brolemann 1916, n. stats., are sister-taxa that differ primarily in epiproctal configurations and comprise Euryurini; sister-taxa Eurymerodesmina and Nannariina Hoffman 1964, n. stats., the latter transferred from Xystodesminae, comprise Eurymerodesmini, n. stat., in which plesiomorphic forms exhibit sublinear, “stick-like,” and subapically curved/bent gonopodal acropodites with moderately-long to long hairs, often with distal tufts, on their “inner” surfaces. Additional transferrals include Wamokia Chamberlin from the xystodesmine tribe Xystocheirini to Xystodesmini (= Harpaphini), and Macellolophus Attems, from Xystodesmidae to Chelodesmidae. Except for Chonaphini, the term, “prefemoral process,” has traditionally been assigned to the secondary and shorter telopodital projection regardless of its position, origin, or configuration. Homology of these different structures has never been demonstrated and requires investigation, but the multitude of differences suggests that they are not such and warrant different names, for example “femoral process,” for the similarly positioned branches in Devillea Brölemann and Rhysodesmus Cook (Xystodesminae: Devilleini, Rhysodesmini). The latter tribe may be polyphyletic, and new tribes may be required for components with acicular “prefemoral processes” (Boraria and Cherokia, both by Chamberlin, Gyalostethus and Erdelyia, both by Hoffman, and Pleuroloma Rafinesque) and the southeastern US genera with small-bodied species (Caralinda Hoffman and Gonoessa, Parvulodesmus, and Lourdesia, all by Shelley). Taxonomic value is accorded the “prefemoral extension/elongation,” which is absent from Eurymerodesmina; complete, encircles the acropodite, and extends for ~1/3 to 1/2 of the latter’s lengths in Euryurini; and incomplete and extends for ~1/4 to 1/3 of the “outer” acropodital surfaces in Nannariina and xystodesmine tribes. Other newly recognized taxonomic characters include the “inner” and “outer” acropodital surfaces/margins, the position on the acropodital stem of the “distal curve/bend,” and the length of the “distal zone.” Rhysodesmus and Sigmoria (Rudiloria) t. trimaculata (Wood) (Xystodesminae: Rhysodesmini, Apheloriini) are recorded from, respectively, Chihuahua, Mexico, and Québec, Canada, as are Xystodesmidae/-inae and, provisionally, Chonaphini, Montaphe Chamberlin, and M. elrodi(Chamberlin), the only plausible taxa for an unidentifiable juvenile from near Yahk and only 2.5 km (1.6 mi) north of the International Border. The southern periphery of interior British Columbia (BC) thus represents the second xystodesmid faunal region in BC and the third in Canada. While incorporation of Euryuridae does not affect the family’s overall distribution, that of Eurymerodesmidae fundamentally alters it by joining the formerly separate East-Nearctic and Meso-American regions into a continuous one extending, north-south, from Montréal Island, Québec, to Santa Ana Department, El Salvador, a distance of around 4,944 km (3,090 mi). Xystodesmidae also inhabit two West-Nearctic regions, one in the interior stretching from southernmost BC to northeastern Oregon and the other running along the Pacific Coast from southern Alaska to southern California. The family also occupies two Palearctic regions, each with three subregions, an eastern one spreading from Hokkaido, Japan, and the southern Maritime Province, Russia, to Taiwan; a point locality in northern Vietnam; and southern/eastern China. The second Palearctic area extends along the Mediterranean and adjoining seas from Morocco, Sardinia, and the southeastern corner of France to Cyprus and southern coastal Turkey. New locality data, references, and maps are provided along with diagnostic accounts of all reconceptualized taxa and new/revived statuses. A simple, sublinear, “stick-like” acropodite with a curve or bend near midlength or subapically and without a secondary telopodital projection is the hypothesized plesiomorphic gonopodal condition in Xystodesmidae. This form has undergone multitudinous modifications/alterations – twists, curls, variably configured thickened and laminate expansions, reductions, bi-/trifurcations, enlargements, ornamentations, etc. that are manifested in today’s xystodesmine tribes. When Avalonia collided with Baltica 450 million years ago, ancestral xystodesmoideans on the former dispersed into the latter, penetrated and occupied vacant niches, and evolved into today’s Melaphina (Euryurinae: Euryurini) and Devilleina (Xystodesminae). A similar evolutionary burst leading to today’s Nearctic and East-Palearctic faunas occurred 10 million years later when Avalonia + Baltica collided with Laurentia to form Euramerica. Ancestral forms of Euryurinae and Xystodesminae again penetrated vacant niches and evolved; the former maintained the general gonopodal structural pattern of Melaphina but changed the epiproct from triangular to broad and spatulate, thereby creating Euryurina. The earliest xystodesmine taxa to evolve in Laurentia were Rhysodesmini and Rhysodesmus, which spread southwestward, penetrated “proto- Mexico, and left relict populations in today’s southern Appalachians. Eurymerodesmina and Nannariina arose from ancestral euryurine stock prior to the Cretaceous in western Appalachia in their present area of overlap. The former dispersed to the west and south while the latter expanded to the east and north; consequently, the Western Inland Seaway minimally impacted Nannariina while eradicating Eurymerodesmina from the inundated area. Today’s populations in the Plains and south-southeastern states therefore represent secondary dispersion in the past 50-60 million years. The Seaway also eradicated Rhysodesmus from these areas, but enough forms survived in high mountain refugia to replenish the fauna when the embayment receded

Variation and pigmentation in the milliped, \u3ci\u3eXystocheir brachymacris\u3c/i\u3e Shelley, 1996, from the northern Sierra Nevada foothills, California, USA (Polydesmida: Xystodesmidae: Xystocheirini)

A newly discovered population of Xystocheir brachymacris Shelley, 1996 (Polydesmida: Xystodesmidae: Xystocheirini), in Placer County (Co.), California, exhibits an unusual grayish-black color dorsally with mottled, ovoid patches at paranotal bases; it cons titutes northern generic and specifi c range extensions of ~28.4 km (17.6 mi). The gonopods differ from those in the El Dorado Co. population in having shorter/acuminate prefemoral processes and blade-like, rather than spatulate, processes “B” that angle away from the solenomere instead of overhanging it. Additionally, a strong distomedial prefemoral lobe, absent from the El Dorado population, arises from the stem in Placer Co. males. Authorship of Xystocheirini is properly attributed to Hoffman, 1980

Gated rotation mechanism of site-specific recombination by ϕC31 integrase

Integrases, such as that of the Streptomyces temperate bacteriophage ϕC31, promote site-specific recombination between DNA sequences in the bacteriophage and bacterial genomes to integrate or excise the phage DNA. ϕC31 integrase belongs to the serine recombinase family, a large group of structurally related enzymes with diverse biological functions. It has been proposed that serine integrases use a “subunit rotation” mechanism to exchange DNA strands after double-strand DNA cleavage at the two recombining att sites, and that many rounds of subunit rotation can occur before the strands are religated. We have analyzed the mechanism of ϕC31 integrase-mediated recombination in a topologically constrained experimental system using hybrid “phes” recombination sites, each of which comprises a ϕC31 att site positioned adjacent to a regulatory sequence recognized by Tn3 resolvase. The topologies of reaction products from circular substrates containing two phes sites support a right-handed subunit rotation mechanism for catalysis of both integrative and excisive recombination. Strand exchange usually terminates after a single round of 180° rotation. However, multiple processive “360° rotation” rounds of strand exchange can be observed, if the recombining sites have nonidentical base pairs at their centers. We propose that a regulatory “gating” mechanism normally blocks multiple rounds of strand exchange and triggers product release after a single round