<Emphasis Type="Italic">In vitro</Emphasis>–<Emphasis Type="Italic">ex vitro</Emphasis> salt (NaCl) tolerance of cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz) plants

Three cassava clones (SOM-1, “05”, and “50”) were cultured in vitro on MS medium plus sucrose (30 g L⁻¹) and myo-inositol (100 mg L⁻¹) without plant growth regulators and with additions of 0 (control), 0.5, 1, 1.5, 2, 2.5, and 3 g L⁻¹ NaCl to test their salt tolerance. The same cassava clones were cultivated in greenhouse conditions on a sandy soil substratum and irrigated with 20% strength Hoagland solution, and additions of 0, 4, and 8 g L⁻¹ of NaCl. Salinity negatively affected the survival, development, leaf water content, and mineral composition (mainly by accumulation of Cl and Na) of both in vitro and ex vitro plants, but with different intensity in each clone. In both conditions of culture (in vitro and ex vitro) clone SOM-1, from a desert arid saline zone of Somalia, was the most tolerant and clone “05”, from a rainy region of Ivory Coast, the most sensitive. Clone “50” tolerance to in vitro salt treatments, although lower, was not significantly different from that of SOM-1 but the ex vitro response was similar to “05”. In general, there was a correlation between in vitro and ex vitro behavior of the cassava plant regarding salt tolerance, which would allow the in vitro culture method to be used for selection of salt-tolerant plants of this crop.     

Continuous cultures of tomato and citron roots in vitro

Summary Initial trials with tomato-root cultures disclosed the desirability of employing a gently agitated liquid medium containing iron in the chelated form. For the normal cultivars “Ace” and “Tropic”, subcultures were best achieved by utilizing sectors that possessed one or more newly emerged laterals. Continuous cultures of a nonlateral-forming tomato mutant, “Diageotropica”, and of citron were accomplished by subculturing tips of the elongating primary roots. The tomato roots were cultured in White's medium with the Fe₂(SO₄)₃ replaced by 0.03 mM NaFeEDTA. Sustained growth of citron-root tips necessitated the use of a medium containing Murashige and Skoog salts, 7.5% sucrose, 100 mg per I each of citric acid and thiamine HCl, and 5000 mg per li-inositol. The success with citron-root cultures was extendable to all cultivars ofC. medica L., but not to otherCitrus species relatives. Both citron and “Diageotropica” root cultures manifested undiminished elongation through repeated subcultures; but neither produced laterals in response to any cultural treatments. Research was supported in part by National Science Foundation Grant OIP75-10390 and Elvenia J. Slosson Fellowship in Ornamental Horticulture.     

ABA contents and the regeneration ability of Fritillaria imperialis L. cultured in vitro

Correlation between ABA content in “mother” tissue and subsequent regeneration ability of Fritillaria imperialis cultured in vitro was investigated. In every experiment regeneration was always most efficient from plant material containing the lowest amount of free ABA: a leafy stem part, bulbs used for micropropagation in October and those stored two months at 30 °C prior to in vitro culture. However, no direct correlation between the absolute amounts of ABA and percentage of regeneration was found.     

Sepecial symposium: In vitro plant recalcitrance in vitro plant recalcitrance: An introduction

Summary In vitro recalcitrance is the inability of plant cells, tissues and organs to respond to tissue culture manipulations. With respect to plant regeneration, recalcitrance can be a major limiting factor for the biotechnological exploitation of economically important plant species and it can also impair the wider application of in vitro conservation techniques. This first paper introduces a compilation of Symposium papers, collectively entitled “Do we understand in vitro plant recalcitrance?”, presented at the 1999 Congress of the Society for In Vitro Biology. The Symposium reviewed recalcitrance in the context of genetic predeterminism, molecular markers and gene expression patterns, whole and explant physiology, stress physiology, habituation, neoplastic progression and plant cancer. The symposium contributors present fundamental and applied investigative approaches which have the potential to enhance our current understanding of in vitro recalcitrance and to assist in overcoming the problems associated with nonresponsive plant cultures. This introductory paper presents the general concept of recalcitrance in relation to whole-plant and explant physiology and considers basic aspects of tissue culture manipulations in the context of recalcitrance problems.     

Expression of phytoene synthase gene (Psy) is enhanced during fruit ripening of Cara Cara navel orange (Citrus sinensis Osbeck)

Citrus is an important fruit crop as regards accumulation of carotenoids. In plant carotenoid biosynthesis, phytoene synthase gene (Psy) plays a key role in catalyzing the head-to-head condensation of geranylgeranyl diphosphate molecules to produce colorless phytoene. In the present paper, we reported the phytoene contents determination and characterization of Psy during fruit ripening of “Washington” navel orange and its red-fleshed mutant “Cara Cara”. Results showed that phytoene was exclusively accumulated in peel and pulp of “Cara Cara”. Although phytoene was observed accumulating with fruit ripening of “Cara Cara”, the contents in pulp were 10 times higher than those in peel. The isolated two Psy cDNAs were both 1520 bp in full length, containing 436 deduced amino acid residues, with a different amino acid at 412th. Genomic hybridization results showed that one or two copies might be present in “Cara Cara” and “Washington” genomes. During “Cara Cara” and “Washington” fruit coloration, expression of Psy was observed to be up-regulated, as revealed by tissue specific profiles in the flavedo, albedo, segment membrane and juice sacs. However, Psy expression in albedo of “Cara Cara” was higher than that in “Washington”, as evidenced by phytoene accumulation in the peel.     

Characteristics of stress response in a mushroom-pathogenic bacterium,Pseudomonas tolaasii, during the interaction withPleurotus ostreatus and carbon/nitrogen starvation in vitro

A brown blotch bacterium,Pseudomonas tolaasii strain PT814, expresses a high degree of cross-protection against generalized stress imposed by physical/chemical treatment, H₂O₂, UV, high temperature, ethanol and NaCl during the interaction withPleurotus ostreatus. Stress resistance was also noted in the bacterium in vitro under limited carbon and nitrogen sources. In addition, changes in cell morphology from a “metabolically active” rod to an “energy-saving” spherical shape were detected during starvation and the interaction. All the changes under stress were reversible. A homologue ofrpoS (σ ^S), a regulator that controls such physiological status during starvation in other bacteria, was identified inP. tolaasii strain PT814. Data suggest that the bacterium is able to withstand a complex stress environment for its survival through changes in its metabolic pattern.     

The effects of external potassium and magnesium concentrations on the magnesium and potassium inflow rates and growth of micropropagated cherry rootstocks, “F.12/1” (Prunus avium L.) and “Colt” (Prunus avium L.) × Prunus pseudocerasus L.)

The effects (and interaction) of two solution concentrations of Mg (50, 500, μM) and two of K (250, 4250 μM) on the growth of micropropagated plants of “F. 12/1” and “Colt” were investigated using a flowing solution culture system. Magnesium inflow and growth of “Colt” and “F. 12/1” were inhibited to a similar extent by an increased concentration of K in the nutrient solution. However, the consequences of this inhibition were different. Reduced inflow of Mg in “F. 12/1” caused Mg deficiency symptoms at high and low concentrations of K, whereas this only occurred with a combination of high K concentration and low Mg concentration in “Colt”. The distribution of dry matter within the plant was significant in determining susceptibility to Mg deficiency. Since “F. 12/1” has a smaller root:shoot ratio than Colt it is unable to sustain the same concentration of Mg in leaves as “Colt” irrespective of external K concentration. The molar ratio of K:Mg in soil solutions should remain <8.5:1 in order to ensure maximum growth of “F. 12/1” and “Colt”. This revised version was published online in June 2006 with corrections to the Cover Date.     

A simple chromosomal marker can reliably distinguishes <Emphasis Type="Italic">Poncirus</Emphasis> from <Emphasis Type="Italic">Citrus</Emphasis> species

Several chromosome types have been recognized in Citrus and related genera by chromomycin A₃ (CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata (“Barnes”, “Fawcett”, “Flying Dragon”, “Pomeroy”, “Rubidoux”, “USDA”) and one P. trifoliata × C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA⁺ banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus × Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm. During the submission of this paper, we analyzed 25 other citrus cultivars with the same methodology and we found that the chromosome marker reported here can indeed distinguish Poncirus trifoliata from grapefruits, pummelos, and one variegated access of Citrus, besides the previously reported access of limes, limons, citrons, and sweet-oranges. However, among 14 mandarin cultivars, two of them displayed a single B/5S-45S chromosome, whereas in Citrus hystrix D.C., a far related species belonging to the Papeda subgenus, this chromosome type was found in homozygosis. Since these two mandarin cultivars are probably of hybrid origin, we assume that for almost all commercial cultivars and species of the subgenus Citrus this B type chromosome is a useful genetic marker.     

Stress response of two coral species in the Kavaratti atoll of the Lakshadweep Archipelago, India

Frequent occurrences of coral bleaching and the ensuing damage to coral reefs have generated interest in documenting stress responses that precede bleaching. The objective of this study was to assess and compare physiological changes in healthy, semi-bleached and totally bleached colonies of two coral species, Porites lutea and Acropora formosa, during a natural bleaching event in the Lakshadweep Archipelago in the Arabian Sea to determine the traits that will be useful in the diagnosis of coral health. In April 2002, three “health conditions” were observed as “appearing healthy,” “semi-bleached” and “bleached” specimens for two dominant and co-occurring coral species in these islands. Changes in the pigment composition, zooxanthellae density (ZD), mitotic index (MI) of zooxanthellae, RNA/DNA ratios and protein profile in the two coral species showing different levels of bleaching in the field were compared to address the hypothesis of no difference in health condition between species and bleaching status. The loss in chlorophyll (chl) a, chl c and ZD in the transitional stage of semi-bleaching in the branched coral A. formosa was 80, 75 and 80%, respectively. The losses were much less in the massive coral P. lutea, being 20, 50 and 25%, respectively. The decrease in zooxanthellar density and chl a was accompanied by an increased MI of zooxanthellae and RNA/DNA ratios in both the species. There was an increase in accumulation of lipofuscin granules in partially bleached P. lutea tissue, which is an indication of cellular senescence. Multivariate statistical analyses showed that colonies of P. lutea ranked in different health conditions differed significantly in chl a, chl c, ZD, RNA/DNA ratios, and protein concentrations, whereas in A. formosa chl a, chl c, chl a/c, phaeopigments and MI contributed to the variance between health conditions.     

Genetic diversity of isolated populations of Nautilus pompilius (Mollusca, Cephalopoda) in the Great Barrier Reef and Coral Sea

Nautilus species are the only remaining cephalopods with an external shell. Targeted heavily by the shell trade across their distribution area, these species have a poorly known population structure and genetics. Molecular techniques have been used to assess levels of inter- and intra-population genetic diversity in isolated populations of Nautilus in the northern sections of the Great Barrier Reef (GBR), Australia and in the Coral Sea. Distinct populations, physically separated by depths in excess of 1,000 m were examined. RAPD analysis of genetic differences showed limited differentiation of the “Northern GBR” populations and the “Coral Sea” populations. Discrimination between the two geographic groups was observed from these data. In addition, partial sequencing of the CoxI gene region, yielded 575 bp of sequence, which was aligned for 43 samples and phylogenetic trees constructed to examine genetic relationships. Two distinct clades were resolved in the resulting trees, representing the “Northern GBR” and “Coral Sea” population groups. Inter- and intra-population relationships are presented and discussed. The differentiation of the Nautilus populations from the Northern section of the Great Barrier Reef and those from the Coral Sea were supported by two distinctly different methodologies and the significance of this separation and the potential evolutionary divergence of these two population groups is discussed.     

Traditional Knowledge and Management of <Emphasis Type="Italic">Feijoa (Acca sellowiana)</Emphasis> in Southern Brazil

Traditional Knowledge and Management of Feijoa (Acca sellowiana) in Southern Brazil. This paper investigates traditional knowledge of the use and management of Acca sellowiana in southern Brazil. Fifty-six informants from three rural communities were assigned to one of four subgroups (“maintainers,” “managers,” “cultivators,” or “users”) based on their responses regarding management and use of A. sellowiana. Traditional knowledge related to use of this species is widespread among rural residents, but traditional knowledge related to management is fragmented depending on whether one uses, manages, or cultivates the species. Knowledge held in rural communities suggests that A. sellowiana could play an expanded role in local economies as well as biodiversity conservation. We suggest that participatory research could stimulate greater local use as well as on-farm conservation of A. sellowiana.     

Coexistence of congeneric spiny lobsters on coral reefs: differences in conspecific aggregation patterns and their potential antipredator benefits

Den sharing by conspecific spiny lobsters (aggregation) is modulated by chemical attraction but may confer several, not necessarily mutually exclusive, antipredator byproduct benefits: a “guide effect”, which only benefits the individual attracted to a sheltered conspecific; a “dilution effect”, which reduces per-capita risk of predation simply through aggregation; or active “group defense”. Each potential benefit has a different set of predictors (relationships between aggregation and conspecific or predator densities), but conflicting results could suggest the simultaneous operation of more than one benefit. These predictions were tested for coexisting Panulirus guttatus (a reef-obligate) and Panulirus argus (a temporary reef-dweller) using data collected during 11 surveys on fixed sites over a coral reef in Mexico. P. guttatus greatly outnumbered P. argus, but P. argus showed a greater tendency to aggregate. All three benefits of den sharing operated for the more social P. argus, with “group defense” being of the most benefit for larger individuals, and the “guide” and “dilution” effects for smaller individuals recently immigrating into the reef habitat and sharing dens with larger conspecifics. P. guttatus did not display “group defense” and its aggregations appeared to be modulated by the interplay between attraction and aggressive behaviors. This species relied more on solitary crypticity, especially at larger sizes, but appeared to benefit from a “guide effect” at high conspecific densities. In experimental tanks, each species tended to aggregate when tested separately, but when tested jointly, aggregation among P. guttatus was significantly reduced. The experimental results reflect the differential patterns of aggregation between the fore-reef, where P. guttatus dominated, and the back-reef, where coexistence of both species was greater.     

Effect of Methyl Jasmonate on Morphology and Dormancy Development in Lily Bulblets Regenerated In Vitro

Scales of lily bulbs are swollen petioles. Lily scale fragments cultured in vitro regenerate bulblets consisting of scales that may or may not carry a leaf blade. The bulblets are dormant and require a cold treatment to sprout. We added the gaseous plant growth regulator methyl jasmonic acid (MeJA) in the headspace of the tissue-culture container and studied the effect on plantlet morphology (scale/leaf-blade formation) and dormancy development in three lilies, Lilium speciosum “Rubrum No. 10,” L. longiflorum “Snow Queen,” and the Asiatic hybrid “Connecticut King.” Methyl jasmonic acid strongly reduced leaf-blade formation in Lilium longiflorum and Connecticut King. This was a specific effect as scale formation was affected much less. The specific inhibition of leaf-blade formation was not observed in Lilium speciosum. In this lily, high concentrations of methyl jasmonic acid (MeJA) inhibited leaf-blade and scale formation to similar extents. Methyl jasmonic acid reduced dormancy development in all three lilies, with the largest effect observed in Connecticut King. In this Asiatic hybrid, almost all bulblets that had regenerated at 300 or 1000 μl l⁻¹ MeJA in the headspace, did not require a dormancy-breaking treatment to achieve sprouting after planting in soil. Previously, it has been found in lily that treatments that reduce leaf-blade formation promote dormancy development. The present findings with MeJA do not agree with this. In the three lilies, the various parameters that were studied—regeneration, scale weight, leaf-blade weight, and dormancy development—were very differently affected by MeJA.     

Observations on Flattened Species of Gracilaria (Gracilariaceae, Rhodophyta) from Taiwan

Four flattened Gracilaria species have been reported from Taiwan: G. spinulosa, G. vieillardii, G. textorii and G. punctata, identified based on branching pattern, the presence or absence of spines, and characters that often vary seasonally. Gracilaria spinulosa was originally described from the type locality, Tainan. Species with toothed margins are usually referred to G. “vieillardii”; those with smooth margins to G. “textorii”, and those with smooth margins and dark spots scattered over the blade to G. “punctata”. Molecular analyses show that specimens with marginal teeth cluster in three different groups: a G. “vieillardii” clade, a G. spinulosa clade, and a clade sister to G. spinulosa. An undescribed species comprises the third clade, which is distinguished by its relatively large gonimoblast cells and weakly developed tubular nutritive cells. The three clades can be separated by the character of the tubular nutritive cells, the size of gonimoblast cells and certain vegetative features. Plants with entire margins form a single clade characterized by cystocarps with basal tubular nutritive cells and their absence in the cystocarp cavity. They are nested in the Hydropuntia complex and are referred to as Gracilaria “punctata” here. The records of G. textorii and G. punctata from Taiwan require reinvestigation in comparison with the Japanese species.     

Pollination biology of <Emphasis Type="Italic">Disanthus cercidifolius</Emphasis> var. <Emphasis Type="Italic">longipes</Emphasis>, an endemic and endangered plant in China

Disanthus cercidifolius Maxim. var. longipes H.T. Chang usually has two inflorescences growing in opposite directions in the axillae, but occasionally three inflorescences grow paratactically. The typical flowering process could be divided into 4 periods: “Pre-dehiscence”, “Initial dehiscence”, “Full dehiscence” and “Withering”. Both the natural population and the planted population had a flowering peak of 15–35 days after the first flower bloomed. There were significant differences between the time courses of flowering of the two populations. Out-crossing is the main breeding system in this species. And autogamy decreases the risk of reproductive failure of this species. The main insect pollinators of D. cercidifolius var. longipes are Episyrphus balteatus de Geer, Scaptodrosophila coracina Kikkawa and Peng, Polistes olivaceus de Geer, Apis cerana Fabricius, Nezara viridula L. and Coccinella septempunctata L., and so on. Among the insects, S. coracina and E. balteatus are the most important and efficient pollinators, but others are inefficient pollinators. Though wind pollination is not efficient, it guarantees reproduction when insect pollinators are not available. “Mass flowering” is an adaptive behavior and reproductive strategy of this species, and “few fruiting” could be caused by the lack of pollinators.     

Lagomorphs from the Miocene of Sandelzhausen (southern Germany)

Three genera of lagomorphs, Prolagus, Lagopsis, and “Amphilagus,” were identified during a revision of the lagomorph material from Sandelzhausen (MN5, Early/Middle Miocene boundary, southern Germany). Evidence of two morphological and dimensional classes were observed at some tooth positions in Prolagus (some p3 show an unmistakable P. oeningensis morphology, others closely resemble P. crusafonti), but not at other tooth positions (e.g., M1–2). Insufficient data from Sandelzhausen precludes identification of two different species of Prolagus from this locality, and to define the characteristics of the possible P. crusafonti-like species. Thus, all Prolagus specimens have been classified as P. aff. oeningensis. The genus Lagopsis is represented by L. cf. penai, whose presence is compatible with a MN5 age. The relative abundance of Lagopsis to Prolagus may indicate relatively cool and wet palaeoclimatic conditions. The largest primitive lagomorph species from continental Europe is present at Sandelzhausen. Morphological and dimensional comparisons with other European primitive lagomorphs exclude any affinity with the genera Eurolagus and Titanomys and with the species included in “Amphilagus ulmensis”. Some common features with “Amphilagus antiquus” were observed, although they are not sufficient for the attribution to this taxon. Until there is a general revision of European primitive lagomorphs, the Sandelzhausen giant lagomorph is classified as “Amphilagus” sp. Its origins, whether from evolution within Europe or migration from Asia, remain unknown.      

Ultra-fastChara myosin: A test case for the swinging lever arm model for force production by myosin

Recent breakthroughs and technological improvements are rapidly generating evidence supporting the “swinging lever arm model” for force production by myosin. Unlike previous models, this model posits that the globular domain of the myosin motor binds to actin with a constant orientation during force generation. Movement of the neck domain of the motor is hypothesized to occur relative to the globular domain much like a lever arm. This intramolecular conformational change drives the movement of the bound actin. The swinging lever arm model is supported by or consistent with a large number of experimental data obtained with skeletal muscle or slime mold myosins, all of which move actin filaments at rates between 1 and 10 μm/sin vitro. Recently myosin was purified, fromChara internodal cells.In vitro the purifiedChara myosin moves actin filaments at rates one order of magnitude faster than the “fast” skeletal muscle myosin. While this ultra fast movement is not necessarily inconsistent with the swinging lever arm model, one or more specific facets of the motor must be altered in theChara motor in order to accommodate such rapid movement. These characteristics are experimentally testable, thus the ultra fast movement byChara myosin represents a powerful and compelling test of the swinging lever arm model.     

New target for rice lodging resistance and its effect in a typhoon

We demonstrated the new target for lodging resistance in rice (Oryza sativa L.) by the analysis of physiological function of a locus for lodging resistance in a typhoon (lrt5) with the near isogenic line under rice “Koshihikari” genetic background (tentatively named S1). The higher lodging resistance of S1 was observed during a typhoon in September 2004 (28 days after heading), when most other plants in “Koshihikari” became lodged. Visual observations showed that bending of the upper stems triggered lodging during the typhoon; the upper stem of “Koshihikari” buckled completely, whereas that of S1 remained straight. In addition to the strong rain and winds during the typhoon, the weight of the buckled upper plant parts increased the pressure on adjacent plants and caused a domino effect in “Koshihikari”. Young’s modulus, an indicator of the rigidity of the culm, was significantly higher in S1 than in “Koshihikari”. In the upper culm, the starch content in S1 was 4.8 times the value in “Koshihikari”, and senescence was delayed in the upper leaves of S1. These results suggest that the rigidity of the upper culm by the higher starch content (as a result of delayed senescence in the upper leaves) may be responsible for the higher lodging resistance during a typhoon in rice. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Variability and structure of natural populations of Elymus caninus (L.) L. and their possible relationship with Hordelymus europaeus (L.) Jess. ex Harz as revealed by AFLP analysis

The AFLP method was used to study the inter-population variability of eight populations of Elymus caninus (L.) L. as well as three populations of Hordelymus europaeus (L.) Jess. ex Harz. In these studies a clear distinction was found between two phenotypes of E. caninus collected in the same locality. It also appeared that two populations of E. caninus representing the “pauciflorum” morphotype were clustered together, similarly as two populations of E. caninus exhibiting morphotype “caninus”. Additionally, the populations of the “pauciflorum” type were clustered together with all samples of H. europaeus. Furthermore, the same approach was applied to analyze the intra-population variability of E. caninus. The populations ranged from nearly uniform to as diverse as the samples collected from different localities. In some populations of this species the presence of off-type plants was revealed. Our data indicate the predominantly self-pollinating character of E. caninus and the possible genetic relationship between of E. caninus and H. europaeus. It is the second paper from the series: Biodiversity of wild Triticeae (Poaceae) in Poland, the first is: Mizianty M. 2005. Variability and structure of natural populations of Elymus caninus (l.) L. based on morphology. Pl. Syst. Evol. 251: 199–216.     

“Meganthropus” cranial fossils from Java

There are now twelve significant hominid cranial fossils from the Lower and Middle Pleistocene of Java, all but two being from the Sangiran site. Most of this material is well-known in the literature, but three skulls, possibly representing “Meganthropus” are here described in detail for the first time. Most scholars have assigned them all toHomo erectus, while others have suggested that they represent as many as four different hominoid taxa. The author argues that they represent two possible species of hominids. “Meganthropus” I, II, and III are more massive than any of the knownH. erectus specimens. They are also relatively higher vaulted, apparently smaller brained, and have unusually thick lower occipital planes. “Meganthropus” may represent a species that separated fromH. erectus upon its arrival to Java.