Trivial Simply Illogical – Reconstructing The Biogeographic History Of The Loranthaceae (Again)

In 2007, a curt but dainty newspaper past times Vidal-Russell & Nickrent provided a scenario for the unfolding of the Loranthaceae, a works life menage unit of measurement of mostly epiphytic tree parasites. Recently, they teamed upward alongside a Chinese grouping (Liu, Le et al. 2018) to supply a new, in addition to totally unexpected hypothesis.
In this post, I’ll live using this standard-made report (pitted alongside to a greater extent than or less unfounded in addition to incorrect statements) as an instance to show:

Common sense would withdraw keep sufficed to come upward to the same conclusion that Liu et al. on the background of the relatively few but long-known unambiguous phylogenetic relationships inside the grouping (Wilson & Calvin 2006; Vidal-Russell & Nickrent 2008a) — nosotros don't demand explicit biogeographic inference to back upward trivial observations.
Address a few shortcomings regarding the analysis, unremarkably found inwards similar studies — mainly, should ane utilisation a European Eocene fossil to inform the minimum historic catamenia of the most-recent mutual ancestor of a clade that is reconstructed as for certain Australasian?
Map the termination of the authors' top-down biogeographic analysis on palaeogeographic maps showing the known fossil tape — maps nosotros (Grímsson, Kapli et al. 2017) published 5 months before Liu et al. submitted their paper, in addition to inwards an opted for the opposite).
Outline what could (have) been done.

The basic province of affairs – fast ancient radiation(s) but geographic lineage sorting

The Loranthaceae [Wikipedia/APW] are non an piece of cake grouping for molecular phylogenetic analyses (Grimm 2017 [PDF]; Grímsson, Grimm & Zetter 2018 — open access/open data). Nevertheless, to a greater extent than or less morphologically defined groups (see Nickrent, Malécot et al. 2010 for the systematics) found readily back upward from the get-go molecular trees (Wilson & Calvin 2006; Vidal-Russell & Nickrent 2008a). Unfortunately, those get-go studies exhibit only cladograms in addition to their information matrices withdraw keep never been published. And the grouping appeared to live deserted. So, when a colleague asked me inwards 2014 to generate to a greater extent than or less molecular phylogenetic framework for their palynological analysis of the menage unit of measurement (Grímsson, Grimm & Zetter 2018; submitted Dec 2016, reviewed past times 2 of the authors of Liu et al., online September 2017), I had to harvest the cistron banks in addition to re-do the analysis alongside what I could find. Which was non optimal, but served our needs.

The maximum likelihood tree shown inwards Grímsson, Grimm & Zetter (2018), using genus consensus sequences generated for 2 nuclear in addition to 3 plastid cistron regions (one non-coding). See my last post for the corresponding figure inwards Liu et al. (2018)

As you lot tin forcefulness out see, to a greater extent than or less clades are straightforward (the tree is rooted alongside the most distinct of the 3 surviving root parasites, Nuytsia, following the results of the 2006 in addition to 2008 papers): long root branches alongside high support. Others, similar the Erytrantheae clade brand sense, but lack back upward (as before, but at that topographic point is also no strong contradictory signal inwards the data). Influenza A virus subtype H5N1 few, e.g. the placement of Aetanthus, are merely or partly incorrect (missing in addition to potentially mediocre data, according to the researcher that uploaded these data). The "backbone", the inter-tribal (-eae)/ -subtribal (-inae) relationships, is largely unresolved (mostly: lack of consistent or discriminating-at-all signal). The only difference betwixt our in addition to the 2006 in addition to 2008 trees (and the 2015 past times Su et al.) is that our doesn't mask the extent of ambiguous signal.

We were just interested inwards placing pollen into a systematic-phylogenetic framework, in addition to for that, the bootstrap back upward consensus network showing the competing alternatives (when existing) served well.

The approach inwards our get-go Loranthaceae newspaper (Grímsson, Grimm & Zetter 2018). Background: a reduced (terminal clades represened past times triangles) bootstrap back upward network rooted alongside Nuytsia; the images exhibit the oft feature pollen for each genus. Green backgrounds – the 3 root parasites, orangish – the strongly different pollen of Tupeia showing a type shared past times many other Santalaes instead of the Loranthaceae-typical triangular grains (which nosotros considered as alternative root, of course of didactics "absurd" as reviewer #1 informed us; but encounter Grímsson, Kapli et al. 2017).

Just past times looking at the to a higher seat Nuytsia-rooted in addition to geographically annotated tree (and the competing alternatives seen inwards the boostrap consensus network), the biogeographic history appears clear (from a modern-day perspective).

The family's source in addition to initial radiations must withdraw keep been inwards Australasia (blue signatures), the habitation of the supposedly get-go diverging root parasite (Nuytsia), many Elytrantheae – an early on diverged subtribe, to a greater extent than oft than non shorter branched (note their relative phylogenetic closeness to the root node) –, an early, rattling distinct but minor branch of Lorantheae ("Clade H" inwards Vidal-Russell & Nickrent 2008a, the Ileostylinae), and, finally inwards ane ("Clade I") of the 2 master copy groups inside the heart Lorantheae ("Clade I+J"). Any other scenario would require multiple dispersals into Australasia, failing Ockham's famous razor. Notably the oldest records of Loranthaceae were all from Tasmania, in addition to the otherwise to the lowest degree diverged modern genus (genetically), the palynologically odd Tupeia (and only non-South American fellow member of the Psittacantheae) is found across (warm temperate) New Zealand. Influenza A virus subtype H5N1 neat fit.

Noting the depression back upward along the backbone, the first radiations were a quick in addition to muddy thing.

The slower-evolving (genetically), all other Psittacantheae in addition to the root parasite Gaiadendron, went west. Vidal-Russell in addition to Nickrent (2007) had the hypothesis of a "proto-Tupeia" (note the naming!) connecting the Gondwana fragments Australasia, Antarctica in addition to South America. Only 2 South Americans are placed apart from the ease inwards our tree (similar inwards before trees), but when ane explores the back upward patterns (when branch back upward is ambiguous, practise exploratory information analysis!) it becomes clear that at that topographic point is no argue to refuse the hypothesis of a unmarried dispersal (note the depression back upward for alternatives, inwards particular the ane seen inwards the tree; but encounter also the accD tree below).

A tree based on the accD plastid cistron information included inwards Su et al.'s (2015) up-to-seven-genes information laid (Grimm 2017, Fig. S6-3). Note the seat of the 2 root parasites in addition to the to a greater extent than oft than non high branch back upward (less taxa, higher support). I wonder why Liu et al. opted against adding to a greater extent than information from this cistron part ... can't Americans in addition to Chinese to acquire their mitt at to the lowest degree on a few Eurasian taxa?

[In 2008 they inferred (much too) immature crown ages in addition to a "basal" root-parasitic degree (ingroup-outgroup long-branch attraction, hither inevitable: fifty-fifty sis families of the Santalales are rattling distinct, thence I didn't include them for our analyses to avoid outgroup-induced branching artefacts). So they modified their theory to the ane re-booted inwards the 2018 paper, get-go the root-parasites radiated in addition to migrated from Australasia, in addition to so the once-evolved aerial parasites followed their footsteps.
PS Taking the immature dates as granted, to a greater extent than or less palynologists wrote (because sure reviewers forced them, too??) that most fossil Loranthaceae inwards the Southern Hemisphere must thence live extinct root parasitic lineages. Palaeontologists, when volition you lot ever larn to read in addition to jurist the character of chronograms? If you lot can't practise it, just enquire somebody who can. Inter-disciplinary exchange, you lot know...]

Influenza A virus subtype H5N1 second master copy lineage, the faster evolving Lorantheae, expanded into Eurasia (note the seat of the purely East Asian genera), alongside ane sublineage reaching Africa. Before doing so, their mutual ancestor(s) manifestly went through to a greater extent than or less bottleneck situations (note the rattling prominent root branch). Bottlenecks are of import for biogeographic analyses, because if something migrates or disperses over long distances, it in all likelihood volition overstep the ane or other. Each bottleneck tin forcefulness out increment genetic uniqueness, the termination are longer branches. Influenza A virus subtype H5N1 (rough) dominion of pollex is the further I go, the to a greater extent than distinct I acquire (genetically). This is why probabilistic biogeographic inferences outperform the former parsimony-based ones.

The range expansion of the Lorantheae from Australasia happened to a greater extent than than once. "Clade G" (the Loranthinae) were the get-go spreading into Eurasia from Australasia. Some dot afterward "Clade I+J", which diverged well-nigh the same fourth dimension than its sibling clades, divide into a staying-home (Australasian) in addition to going-abroad (into East Asia) party. And spell the staying-home political party did follow afterward (the yellowish dots inwards Clade I), the East Asian political party ("Clade J") expanded into western Eurasia in addition to Africa, in addition to a few went dorsum to the former home. Loranthaceae are largely tropical-subtropical groups (with a few, but interesting outposts inwards the temperate zone) alongside high dispersal capacity (also found across South Pacific Islands), such groups tin forcefulness out freely migrate betwixt the modern-day Indomalayan in addition to Australasian realms (essentially no barriers; encounter also 2 of the 3 examples I used for my Median network advertisement post: Ixora and Hoya).

Distribution of master copy Loranthaceae lineages. Pink = New World Psittacantheae alongside an outpost inwards New Zealand, Tupeia, the genus without Loranthaceae-typical pollen (fields within: the mono- or ditypic root parasite Gaiadendron); yellowish = Old World-Australasian Lorantheae; bluish margin = Elytrantheae; calorie-free green, Nuytsia, the genetically most distinct genus in addition to representing the putative first-diverging lineage.

Because it's trivial from a modern-day perspective, but non so when looking at the fossil tape [Palaeogene/Neogene], nosotros (Grímsson, Kapli et al. 2017) did several molecular dating experiments (using in addition to testing different rooting scenarios in addition to including only ingroup fossils) but no explicit phylogeographic inference when describing novel Loranthaceae pollen from the Northern Hemisphere. Because the needed information were missing. Liu et al. re-produced our dating results (re-using 2 of our fossil) in addition to filled this gap inwards knowledge.

Liu et al.'s explicit biogeographic reconstruction

Of course, mutual sense as applied to a higher seat (demeaned as "explanatory" inwards today's pseudo-hard biological sciences) is non enough. Only explicit inferences tin forcefulness out tell us how it is (was). So, what did Liu et al. observe instead using a much amend information laid (I assume, the authors are non allowed sharing their data, encounter my lastly post [PDF alongside the correspondance]) in addition to beingness guided past times the nigh-expert on these plants? It tin forcefulness out live seen inwards their graphic abstract (the newspaper itself is paywalled, in addition to the used information matrix naturally non accessible).

Including the sis families as outgroup (and a mayhap artefactual outgroup-based root) in addition to up-to-date analyses methods they observe ... the same.

The Loranthaceae all come upward from Australasia (here defined using Wallace's famous line, which has never actually been a slap-up barrier for plants), in addition to spell to a greater extent than or less stayed (two of the root parasites in addition to the Elytrantheae), others went early on into the Americas via Antarctica (Gaiadendron, Psittacantheae).

Not long after this get-go radiation, to a greater extent than or less of the Lorantheae escaped Commonwealth of Australia into Asia (and maybe dorsum ane time again to a greater extent than recently) to colonise Africa ("after" thirty Ma) in addition to Europe ("after" 10 Ma).

Trivial situations volition give trivial reconstructions.

When all members of a lineage are African, whatsoever method, no thing how fancy, volition reconstruct Africa as the ancestral expanse of this lineage (see also this open access paper, showing similarly surprising results, at that topographic point are many to a greater extent than of this form — don't live disappointed, the championship is a flake misleading).
When the earliest diverged in addition to to the lowest degree diverged members of a focal grouping are Australian, it's likely that Commonwealth of Australia was the habitation of the mutual ancestor.
If 2 regions are mixed (e.g. Australasians in addition to Asians), the dot of source is to a greater extent than likely the ane found inwards the get-go diverging sublineages, unless they are much to a greater extent than distant to the according root node.

And where it's non trivial, well, in addition to so the reconstructions volition acquire by to decide, also (see the reconstruction for the deeper in addition to deepest nodes inwards Liu et al.'s area-chronogram). The only but of import difference is that probabilistic methods volition give you lot values to play with, alternatives nosotros tin forcefulness out verbalize over (rarely done), whereas the former parsimony-based methods just produced a large enquiry grade or something unreasonable (fun-fact: nosotros ane time submitted a newspaper to exhibit that, a decade agone using our beloved Fagus as a case, but it got lost inwards the Forest of Reviews). Plants are to a greater extent than oft than non trickier than animals regarding biogeography, they don't courtroom to mate, in addition to many don't bother well-nigh H2O bodies (including large ones, encounter e.g. Denk, Velitzelos et al. 2015). But if there's e.g. non plenty pelting during growing season, or also much snowfall in addition to frost inwards winter, it's direct no-go expanse (see my post in addition to D. Morrison's The Wine Gourd post well-nigh Köppen in addition to vine).

[PS Renner (2004) provides a dainty review on trans-oceanic dispersal inwards tropical plants alongside to a greater extent than or less relevance for Liu et al.’s discussion. They cite it in addition to utilisation the concept to explicate the “long-distance dispersal” in addition to “disjunction of Loranthaceae betwixt continental Africa in addition to Madagascar” – hardly long distance … but getting from Commonwealth of Australia to Asia inwards the Eocene is a different thing.]


The lineage-through-time plot inwards Grímsson, Kapli et al. 2017, the newspaper nosotros published 5 months before Liu et al. submitted theirs where this termination (Scenario four equals their preferred topology) is reproduced (see below) in addition to discussed (broadly) as really new.

Illogic assumptions in addition to interpretations

The devil lies inwards details. Liu et al. did (like so many others) non exhibit a phylogram, only a cladogram in addition to chronograms. So, nosotros withdraw keep footling thought well-nigh the primary branch lengths, the amount of alter inside in addition to betwixt the clades. I can't exhibit a phylogram, either, because their expert co-author advised the corresponding writer to non transportation me the information matrix they used.

[Maybe a phylogram tin forcefulness out live found inwards the online supplement, but it's also paywalled. Thank you, Elsevier, for your dedication to move along scientific discipline nether the lid.]

Let's first facial expression at the used constraints to create minimum ages (see also my comment on ResearchGate in addition to this post). Liu et al. write inwards Material & Methods:

Most fossils recognized as Santalales are represented past times pollen grains of Cretaceous in addition to Tertiary historic catamenia (Vidal-Russell in addition to Nickrent, 2008b). We gave 2 fossil calibrations for the outgroups of Loranthaceae. The crown historic catamenia of the tribe Anacoloseae of Aptandraceae was constrained to seventy Ma (95% HPD: 66.0–72.1 Ma) based on the fossil of Anacolosidites recorded since the Maastrichtian (Malécot in addition to Lobreau-Callen, 2005). The fossil pollen of Misodendrum (as Compositoipollenites)
was recorded from middle Eocene (ca. 45 Ma) (Zamaloa in addition to Fernández, 2016). Hence the crown historic catamenia of Misodendraceae [Misodendron is sis to all others] was constrained to 45 Ma (95% HPD: 41.2–48.6 Ma). The stem historic catamenia of Loranthaceae was constrained to seventy Ma (95% HPD: 69.4–72.6 Ma) based on the fossil of Cranwellia (Mildenhall, 1980; Macphail et al., 2012) [as inwards Vidal-Russell & Nickrent 2008, on its ain leading to much also immature estimates for the Loranthaceae; Grímsson Kapli 2017, hence...] The crown node of the tribe Lorantheae was constrained to 42.8 Ma (95% HPD: 37.8–47.8 Ma) according to the fossil pollen Changchang MT identified as Taxillus, Scurrula and Amyema (Grímsson et al., 2017b). The crown node [= most-recent mutual ancestor, MRCA] of the tribe Elytrantheae was constrained to 39.6 Ma (95% HPD: 38–41.2 Ma) according to the fossil pollen Profen MT3 (Grímsson et al., 2017b).

Mostly next our suggestions: for each pollen type described, nosotros included a Use-as-age-constraint paragraph. We also used the Changchang MT as constraint for a minimum stalk (root) historic catamenia of the heart Lorantheae (clade I+J), which inwards Liu et al.'s tree equals the Lorantheae crown node.
Same for the Profen MT3 in addition to its Elytrantheae-like counterparts, which Liu et al. even so decided to position ane node upward (reason may live stated inwards the paywalled supplement).

Use as historic catamenia constraint
Here nosotros used Profen MT3, MT4 in addition to MT5 to constrain the root historic catamenia of the Elytrantheae, i.e. the minimum historic catamenia of the MRCA of Notanthera in addition to Elytrantheae (scenarios 1–3). Further studies of modern pollen of Elytrantheae at in addition to below the genus plane in addition to to a greater extent than genetic information are needed [hasn't been done] to determine whether the Profen MT3, in addition to the related Profen MT4 in addition to MT5, are already indicative for a get-go difference inside the Elytrantheae in addition to tin forcefulness out live placed to a greater extent than decisively inside the Elytrantheae subtree.

Since nosotros withdraw keep no thought well-nigh the exact historic catamenia of the stratigraphic unit of measurement inwards which nosotros found these pollen grains, nosotros didn't constrain the mid-points 42.8 (late Lutetian) or 39.6 Ma (mid-Bartonian) but drew a random historic catamenia from the possible fourth dimension interval: 47.8–37.8 Ma for the Changchang MT in addition to 41.2–38 Ma for the Profen MTs (details provided inwards our openly accessible, doi-ed Supplement File S1 — the beauty of publishing inwards PeerJ and non Elsevier's dustbins!).

But according to Liu et al.'s biogeographic inference, the MRCA of the Elytrantheae, fixed to ±43 Ma, was in all likelihood Australasian, but the pollen is from just the other side from the world! Quite an enigma.

But piece of cake to solve:

Either ane includes this information well-nigh past times distribution inwards the analysis: the Elytrantheae were non Australasian as reconstructed, but quasi-ubiquitous at 43 Ma (we would non forcefulness them to live just European, because at that topographic point are as former Loranthaceae pollen inwards Commonwealth of Australia that – when studied using high-resolution SEM microscopy may good include Elytrantheae).
Or, nosotros translate the European Elytrantheae as an extinct sis lineage of the surviving, originally Australasian Elytrantheae; adding a shadow node (at 43 Ma) in addition to accordingly coded OTU (near-zero tip) into our ultrametrised tree.

For the Changchang MT, nosotros withdraw keep the same problem, only that it is non so bothersome. The MRCA of Lorantheae is in all likelihood Australasian (and discussed as such), but also may live Asian alongside a probability of 33% according the reconstruction (something the authors to a greater extent than oft than non ignore). This is a goodness instance why ane should rely on a probabilistic framework inwards biogeography, but still should move along inwards hear the construction of the tree.

All 3 master copy Lorantheae lineages, the diffuse (geographically) Loranthinae, the Australasian Ileostylinae, in addition to the in all likelihood original Asian Core Lorantheae withdraw keep prominent roots.
The tips of the subclades differ: although Loranthinae in addition to Ileostylinae are a flake closer to the Lorantheae-MRCA (phylogenetically, i.e. root-tip distance via the tree), they are non closer than the Asian members of the Core Lorantheae clade, but their Australasian in addition to fifty-fifty to a greater extent than their African siblings are to a greater extent than oft than non longer branched.
The 2d node inwards the Lorantheae subtree (the MRCA of Loranthinae in addition to Ileostylinae) is rattling short-branched in addition to lacks support.

The maximum likelihood bootstrap consensus network for Su et al.'s Loranthaceae matK data (likely the same than used past times Liu et al.) This plastid cistron enforces the basic tree topology, light-green edges refer to those seen inwards the "7-gene" cistron tree, competing or matK-preferred alternatives (Grimm 2017, Fig. S6-4). Note the amiguity regarding primary relationships inside aerial parasites, including the human relationship betwixt the 3 master copy Lorantheae groups.

If the out-of-Australia hypothesis is a goodness ane for the Lorantheae, this agency that the mutual ancestors of all 3 Lorantheae lineages underwent a massive bootleneck, before they could re-radiate, including those that stayed dorsum home: a unmarried or 2 species survived in addition to ane or 2 escaped.

Or, the mutual ancestors of all Lorantheae underwent a quick, large radiations spreading across Eurasia in addition to Australasia, in addition to so their subsequent areas broke upward in addition to remained isolated for quite a time: subtropical-temperate (western) Eurasia – Loranthinae, tropical (South in addition to East) Asia – Core Lorantheae, Australasia – Ileostylinae.

Which of those hypotheses is true, cannot live decided past times top-down molecular inferences (both tin forcefulness out explicate the basic molecular differentiation patterns), but would require a amend grasp on the actual fossil tape of the 3 lineages. Liu et al. decided to ignore this only (it didn't fit their trivial reconstruction), but our Eocene/Oligocene pollen inwards Europe includes forms that are mayhap rattling early on Loranthinae, in addition to for certain Lorantheae (including their precursors, i.e. stalk Lorantheae), in addition to Loranthinae pollen tin forcefulness out live found still inwards the Miocene. In contrast to what Liu et al. discuss, the Loranthus-lineage could withdraw keep easily survived the Plio-Pleistocene climate fluctuations inwards mild-temperate/subtropical refuges similar their master copy hosts (Fagaceae: oaks, beeches in addition to relatives) until today (Loranthus has a warm temperate Köppen signature, in all likelihood non so different cast e.g. oaks of sections Cerris and Ilex; cf. Denk et al. 2013, 2017; Grímsson et al. 2016).

Another thing that completely run unchecked past times the confidential peer review is the full general misconception of the authors that node dating estimates fixed past times fossils stand upward for exact dates or fifty-fifty maxima. In the entire give-and-take the authors refer to "at" in addition to "after" xxx Ma, but what they withdraw keep are minimum estimates. For instance, they write "Our results exhibit that African Loranthaceae are the younger members of the family, having originated after 28.47 Ma (Fig. 3), i.e. the Chattian of the Oligocene" — no, they don't. They exhibit that the African Loranthaceae diverged latest in the Oligocene (mean 28.47 [median would live better]; 23.95–33.54; Liu et al.'s Table 2). See also our 2017 paper.

Our 2017 dated Loranthaceae tree ...

... in addition to Liu et al.'s (2018) dated Loranthaceae tree (inlet their lineage-through-time plot). Make your alternative (it doesn't actually matter, does it?)

We thence wrote before discussing our (very similar regarding the estimates) results:

"Due to the data-related limitations regarding both the molecular information in addition to the fossil record, our dating analysis set-up tin forcefulness out only supply absolute minimum estimates for difference ages inwards the Loranthaceae."

In contrast to many of my beau palaeobotanists, I withdraw keep a sure love for molecular dating, but don't pretend it's an exact science. Any guess is as goodness as the information behind it, in addition to inwards the instance of Loranthaceae those information needs a lot to a greater extent than work.

This is specially truthful for the African loranths in addition to the Lorantheae inwards general. Being a subtropical-tropical grouping living on other trees, Loranthaceae in all likelihood didn't bound into Africa when subtropical in addition to tropical forests were on the retreat, but before that (during the much warmer Eocene). But it may withdraw keep been the fourth dimension of their isolation from their South in addition to East Asian (and potential extinct western Eurasian) relatives. (PS The so-far lack of Loranthaceae pollen for Africa is likely a sampling artefact; when using high-resolution SEM imaging, they tin forcefulness out live found also inwards African pollen assemblages; Grímsson, Xafis et al. 2018 — open access; animal-pollinated plants tin forcefulness out live tricky to find, fifty-fifty when they withdraw keep rattling unique in addition to piece of cake to seat pollen grains; in addition to the torrid zone are to a greater extent than oft than non not optimal for finding works life fossils.)

Mapping into the past times – a litmus attempt out for biogeographic inferences

Let's assume Liu et al.'s biogeographic inference depicts the truth (technically, it's fairly correct) in addition to map it on the past times Earth. Since this is non a scientific newspaper but a post showing why nosotros should practise such things, I'll just utilisation the maps of Grímsson, Kapli et al. (© Ron Blakey) alongside the fossil tape shown, for a 1:1 comparison.

By the Paleocene, Nuytsia was already isolated according to Liu et al., but the fossil records doesn't move that deep, so nosotros skip the Paleocene.

Modified from Grímsson, Kapli et al. (2017), fig. 10.

If nosotros convey Liu et al.'s (matching ours) estimates as minima, nosotros encounter quite a fit alongside the actual fossil tape (determined: coloured stars, in addition to undetermined: white stars). The master copy shortcoming of the explicit biogeographic reconstruction as performed hither is that the modern distribution patterns (of the survivors) are likely non comprehensive for their lineages. Liu et al. silently accepted this for the Elytrantheae (by using our European fossil as historic catamenia constraint for the Elytrantheae MRCA), but decided to non verbalize over this in addition to to ignore our other Northern Hemispheric pollen of the Psittacantheae/Psittacanthinae in addition to the likely get-go representatives of the Australasian-East Asian (at the time) Lorantheae: "The major extant lineages of Loranthaceae differentiated inwards Australasia in addition to South America betwixt thirty in addition to 44 Ma, but during this fourth dimension the ancestor of Loranthaceae that occurred inwards North America, Greenland in addition to Europe became extinct". Case closed.

It's southern activeness only, why ane time again tin forcefulness out nosotros utilisation 2 northern hemispheric fossils as the only ingroup constraints? And what ane time again makes you lot retrieve that something tin forcefulness out bound from subtropical-temperate Commonwealth of Australia into tropical Asia, but doesn't move all the way along the closing Tethys into Europe (like all the other tropical stuff)? This is why you lot unwrap something similar this inwards a mag titled: Molecular Phylogenetics & Evolution, where palaeobotanical reviewers are rare, in addition to easily outruled past times the phylogenetic experts judging your piece of occupation (well, nosotros don't know if it just a rumour or true, because the peer review procedure is confidential).

Liu et al. verbalize over Antarctica as bridge, in addition to specially the Nothofagaceae, as the carriers for dispersal into South America. But Nothofagaceae are a subtropical-temperate grouping (distinctly the latter inwards South America). Antarctica was mild but non tropical during the Eocene climate optimum. So, the huckpack-loranths went into the temperate zone to colonise the neotropics. And why shouldn't they practise the same on the Fagaceae, according to Liu et al. to a greater extent than or less other of import host? Fagaceae were already at that topographic point inwards the northern hemisphere, in addition to nearly everywhere. They are at to the lowest degree eighty Ma old, in addition to specially the tropical-subtropical members withdraw keep a vast fossil tape from the terminate of the Cretaceous into the Paleocene (we published a nice, open access newspaper inwards this context inwards 2016). Which would explain, why ane finds so many unique southern hemispheric pollen types inwards the Eocene of Central Europe. It was hot subtropical to tropical, in addition to total of hosts (see supplements to Grímsson, Kapli et al. 2017, Grímsson, Grimm & Zetter 2018).

In cools downwardly inwards the Neogene, in addition to so does the amount of known Loranthaceae pollen, but Commonwealth of Australia is moving steadily towards nicely warm latitudes.

Modified from Grímsson, Kapli et al. 2017, fig. 11. PS Influenza A virus subtype H5N1 serial of rattling detailed palaeotopographic world maps tin forcefulness out live found inwards Christopher Scotese's ResearchGate projection entitled Earth History: The Evolution of world Systems.

Another odd thing is that the reconstruction assumes rather dramatic cross-ocean dispersal events inwards the past times (repeatedly betwixt a still rattling southern Australia, which for to a greater extent than or less argue was ever a multifariousness hotspot for the group, in addition to distant Asia), which stopped inwards the Neogene. Although the South Americans went into North America in addition to possible Europe, they never managed to acquire to Africa or expand into (East) Asia (in contrast to to a greater extent than or less of their hosts). No cross-oceanic actual long-distance dispersal from Republic of Republic of India west-wards. Once established inwards Africa, this sublineage of the heart Lorantheae never went back, non fifty-fifty during the mid-Miocene climatic optimum. Neither did other Eurasian lineages follow their example. Which is quite a difference to other subtropical-tropical groups alongside high dispersal capacity, where nosotros tin forcefulness out observe genetically (near)identical species inwards eastern Africa in addition to southern Asia; in addition to the birds mentioned so prominently inwards the championship (you withdraw keep to hold back till the lastly department of the give-and-take to encounter why, p. 209; I couldn't help laughing out loud when reading there: "Additionally, our dating results indicated that aerial parasitism arose ca. 48–50 Ma" – something nosotros showed already inwards our dating paper, but were cautioned against jumping to quick conclusions; you lot say potato...)

Did the Loranthaceae lost their drive? Maybe. Alternatively, what nosotros encounter today is mainly former established areas (Eocene in addition to older, in addition to mayhap including Africa), non so different from the former theories Liu et al. discard without providing whatsoever counter-evidence. Not classic Gondwana Breakup, but something that roots inwards a global distribution (and link) of Loranthaceae past times the terminate of the Mesozoic, dawn of the Cainozoic; a fourth dimension when angiosperm-dominated forests were on the steep rise. With the World recovering from the Big Chill (the "K-T-Event"), this footing allowed them to speedily diversify during the Paleocene-Eocene climate optimum. Globally. Or to convey the chance to displace into the tropics. Keep inwards mind: minimum ages. And given their particular biological scientific discipline as epiphytic parasites depending on animals to disperse, I tend to retrieve that when nosotros observe a pollen the according lineage is already at that topographic point alongside total forcefulness in addition to maybe fifty-fifty for a flake of fourth dimension (personally, I still fancy the original scenario position upward past times Vidal-Russell in addition to Nickrent inwards 2007 alongside slight modifications).

In this context a coarse but rattling interesting palaeo-Köppen map produced inwards course of didactics of a French report (Chaboureau et al. 2014; but non published inwards the paper), that nosotros also used for a supplementary figure to Grímsson, Grimm et al. 2018.

A palaeo-Köppen map for the world seventy 1000000 years ago, latest Cretaceous before the Big Chill (provided past times A. Franc, generated inwards course of didactics of the enquiry to Chaboureau et al. 2014). This is the fourth dimension when Loranthaceae supposedly originated inwards Austral(as)ia (constrained inwards Liu et al. 2018 in addition to Vidal-Russell & Nickrent 2008b using Cranwellia). Tropical = Köppen's A-climates, Arid = B-climates (dry climates), Temperate = C-climates (warm temperate climates), Cold = D-climates (snow or boreal climates), Polar = E-climates. See also this post explaining the (in)difference betwixt subtropical in addition to (warm) temperate.

Alain Franc, a co-author who introduced me to these maps (unfortunately still unpublished inwards this form; their reviewers preferred them showing the biomes non the Köppen climate zones inwards the paper, which I observe a bad decision), told me the reconstructions tend to live also mutual depression temperature towards higher latitudes in addition to the further ane goes dorsum inwards time. But it's rubber to say: If the first, belatedly Cretaceous loranth was Australian, it was non a tropical rainforest species. And when they became tropical (late Paleocene, as nosotros wrote: estimates should live treated as absolute minima) it would withdraw keep been easier to measurement from South America into Africa than from (still) warm temperate Commonwealth of Australia via putative (tiny) islands into tropical Asia. But ane time they established inwards tropical Asia, at that topographic point would withdraw keep been no barrier to migrate into Europe (and Africa). Like an Elytrantheae inwards the Eocene of Europe. Or stalk Lorantheae. While the Psittacantheae came from the W the ane or other way, depending whether it was tropical-subtropical (cross-oceanic) or subtropical-temperate (via North Atlantic Land Bridge) lineages. Influenza A virus subtype H5N1 lot is possible in addition to could explicate the modern-day molecular differentiation patterns.

Where to move from here

Biogeographic histories, similar whatsoever historical research, greatly practise goodness from historical bear witness (something leading biogeographers of the lastly century strongly objected against). But at that topographic point are also many white stars inwards our maps. When nosotros actually desire to empathise how the Loranthaceae lineages radiated in addition to migrated inwards the past times in addition to how this correlates to the expanding in addition to shrinking tropical in addition to subtropical woods biomes (their master copy home), ane first needs to analyse also the southern hemispheric pollen tape using high-resolution microscopy. Which pollen type practise the oldest finds inwards Commonwealth of Australia in addition to Tasmania show? Do nosotros encounter a multifariousness matching our dated trees (which predict several Loranthaceae, root in addition to aerial parasitic lineages beingness nowadays at the time)? There are quite a flake Gothanipollis in literature, but at the instant nosotros just tin forcefulness out say that they are Loranthaceae. Studied using SEM, nosotros may live able to say much to a greater extent than (Grímsson, Kapli et al. 2017; Grímsson, Grimm & Zetter 2018, in addition to palynological literature cited therein). In the best case, this volition supply ane alongside plenty fossils to practise a family-wide fossilised birth-death dating (which is a slap-up thing for plants, too, when you lot withdraw keep plenty fossils) in addition to (if ane feels, it's necessary) actual ancestral areas that could live included inwards an explicit biogeographic inference.

With honour to the imbalanced branch-length patterns in addition to oft long terminal branches, ane volition demand African fossils (one has already been found; Grímsson, Xafis et al. 2018), and, inwards general, fossils closer to the tip of the Loranthaceae tree. I would brand whatsoever bet that the currently Oligocene stalk historic catamenia for the African clade volition live the get-go to tumble. The results for the Loranthus/Loranthinae lineage shows that it currently doesn't add together upward for the leaves of the Loranthaceae tree.

Molecular data-wise, ane should trim the issue of taxa in addition to attempt to increment the issue of conservative (ideally nuclear) cistron regions.
Conservative genes because it is a relatively fast evolving group, in addition to it makes footling sense to include outgroups alongside cistron regions extremely different from those used for the ingroup (personally, I never saw the dot inwards adding an outgroup at all, when the aim is to report ingroup diversification).
Ideally nuclear, because the plastid matK already has an thought well-nigh the maternal lineage, but the signal inwards the combined 18S in addition to 25S rDNA data, biparentally inherited cistron regions from the same functional, multi-copy unit, is far from beingness conlusive.
Adding leaves (OTUs) rattling distant from the nodes ane tin forcefulness out constrain using fossils, is counterproductive as well. What's the dot including 20/30 OTUs alongside partly substantially different terminal branch-lengths in addition to inflicting non few ambiguous signals for a geographically homogenous clade when the divergences, nosotros are looking at happened twoscore or to a greater extent than 1000000 years ago? One should brand sure non to add together information that just increases the terminal noise. Because ane thing is likely inwards such an active grouping of plants: the closer nosotros acquire to the leaves, the to a greater extent than nosotros withdraw keep to bargain alongside non-dichotomous evolutionary processes, hence, reticulate, tree-unlike signals.

A sort-of-tanglegram we showed inwards our 2017 paper to brand the reader aware of the molecular information situation. Note that although at that topographic point are no high-supported conflicts regarding basic relationships, it becomes quite chaotic towards the leaves. Pity, that at that topographic point are no mutual standards on information documentation in addition to presentation. I'd withdraw keep loved to encounter the corresponding graph based on Liu et al.'s amend information laid (same cistron regions).

A likely profitable palaeopalyno+genetic projection would live an in-detail report of the Psittacanthinae, the master copy clade inwards the Americas. They withdraw keep rattling various pollen; different types tin forcefulness out live found fifty-fifty inside genera Feuer & Kuijt (1979, 1980, 1985). Knowing when in addition to where they pop-up (we found unambigous Tripodanthus-pollen inwards North America in addition to Greenland, but it may live the primitive type of the entire lineage) volition eventually allow going beyond minimum historic catamenia node dating (allow a fossilised-birth-death dating; Heath, Huelsenbeck & Stadler 2014) in addition to mayhap infer a detailed history of the Loranthaceae inwards the New World. Revisiting the American Loranthaceae pollen tape (and seeking out to a greater extent than of them) volition live crucial. But it only makes sense when this subtribe gets finally to a greater extent than or less substantial attending past times molecular phylogeneticists, in addition to across its entire geographic range. In Liu et al.'s tree (and its rattling similar ancestors), the most pollen-diverse genus, Psittacanthus, is represented past times a unmarried accession; Passovia by a species alongside odd (for the genus), likely derived pollen (and a species representing to a greater extent than or less other genus, Phthirusa, according Kuijt 2011, which makes pollen-wise sense), in addition to 2 genera alongside quite interesting in addition to partly overlapping pollen morphologies, Cladocolea and Struthanthus, alongside ane in addition to 2 representatives. Influenza A virus subtype H5N1 argue maybe that if to a greater extent than speces are included to infer molecular phylogenetic relationships inside this so far well-resolved group, to a greater extent than or less of genera may desintegrate/need to live modified. But maybe molecular lineages concur amend alongside the pollen morphology (studied nearly twoscore years ago...) than electrical flow taxonomy. And pollen is the only viable ticket into the past. Such a report could live a blue-print for cross-disciplinary research: studying genes in addition to pollen of the same extant material, to facilitate the latter's utilisation inwards dating in addition to biogeographic studies when popping upward inwards the fossil record.

Last but past times far non least, ane should give palaeo-Köppen (my preference)/ palaeo-biome (PNAS peers' preference) maps a try. Characterising the modern Loranthaceae lineages (two examples: Grímsson, Potts et al. 2018 — pyrite opened upward access; Rubel et al. 2018 — gold opened upward access), in addition to and so encounter where the reconstructions exhibit the corresponding climate niches/ biomes at (before when using node dating) the times when the various master copy lineages diverged (evolved).

It strikes me a grouping to boldly move where no-one has gone before.

And worth the attempt because judging from Liu et al. (2018) in addition to the papers before inwards the lastly decade, the nigh-expert (American professor emeritus) currently controlling this enquiry is non ready to evolve as much as his report objects (just cheque out the cited papers). And fifty-fifty though he may move along his group's matrices away from the public, the information volition eventually live uploaded to cistron banks.

Cited literature
Chaboureau A-C, Sepulchre P, Donnadieu Y, Franc A. 2014. Tectonic-driven climate alter in addition to the diversification of angiosperms. Proceedings of the National Academy of Sciences 111:14066–14070.
Denk T, Grimm GW, Grímsson F, Zetter R. 2013. Evidence from "Köppen signatures" of fossil works life assemblages for effective estrus carry of Gulf Stream to subarctic North Atlantic during Miocene cooling. Biogeosciences 10:7927–7942. Denk T, Velitzelos D, Güner HT, Bouchal JM, Grímsson F, Grimm GW. 2017. Taxonomy in addition to palaeoecology of 2 widespread western Eurasian Neogene sclerophyllous oak species: Quercus drymeja Unger in addition to Q. mediterranea Unger. Review of Palaeobotany in addition to Palynology 241:98–128.
Denk T, Velitzelos D, Güner HT, Ferrufino-Acosta L. 2015. Smilax (Smilacaceae) from the Miocene of western Eurasia alongside Caribbean Area biogeographic affinities. American Journal of Botany 102:423–438.
Feuer SM, Kuijt J. 1979. Pollen development inwards the genus Psittacanthus Mart. Fine construction of mistletoe pollen II. Botaniska Notiser 132:295–309.
Feuer SM, Kuijt J. 1980. Fine construction of mistletoe pollen III. Large-flowered neotropical Loranthaceae in addition to their Australian relatives. Annals of the Missouri Botanical Garden 72:187–212.
Feuer SM, Kuijt J. 1985. Fine construction of mistletoe pollen VI. Small-flowered neotropical Loranthaceae. Annals of the Missouri Botanical Garden 72:187–212.
Grimm GW. 2017. ‘Quick-and-dirty’ re-analysis of the Su et al. (2015) information of Loranthaceae in addition to their sis groups. File S6 to Grímsson et al., Evolution of pollen morphology inwards Loranthaceae. Grana 57 [Online supplement].
Grímsson F, Grimm GW, Meller B, Bouchal JM, Zetter R. 2016. Combined LM in addition to SEM report of the Middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin, Austria: Part IV. Magnoliophyta 2 – Fagales to Rosales. Grana 55:101–163.
Grímsson F, Grimm GW, Potts AJ, Zetter R, Renner SS. 2018. Influenza A virus subtype H5N1 Winteraceae pollen tetrad from the early on Paleocene of western Greenland, in addition to the fossil tape of Winteraceae inwards Laurasia in addition to Gondwana. Journal of Biogeography 45:567–581. Grímsson F, Grimm GW, Zetter R. 2018. Evolution of pollen morphology inwards Loranthaceae. Grana 57:16–116.
Grímsson F, Kapli P, Hofmann C-C, Zetter R, Grimm GW. 2017. Eocene Loranthaceae pollen pushes dorsum difference ages for major splits inwards the family. PeerJ 5:e3373 [e-pub].
Grímsson F, Xafis A, Neumann FH, Scott L, Bamford MK, Zetter R. 2018. The get-go Loranthaceae fossils from Africa. Grana 57:249–259.
Heath TA, Huelsenbeck JP, Stadler T. 2014. The fossilized birth–death procedure for coherent calibration of divergence-time estimates. Proceedings of the National Academy of Sciences 111:E2957–E2966.
Kuijt J. 2011. Pulling the skeleton out of the closet: resurrection of Phthirusa sensu Martius in addition to consequent revival of Passovia (Loranthaceae). Plant Diversity in addition to Evolution 129:159–211.
Liu B, Le CT, Barrett RL, Nickrent DL, Chen Z, Lu L, Vidal-Russel R. 2018. Historical biogeography of Loranthaceae (Santalales): Diversification agrees alongside emergence of tropical forests in addition to radiations of songbirds. Molecular Phylogenetics in addition to Evolution 124:199–212.
Nickrent DL, Malécot V, Vidal-Russell R, Der JP. 2010. Influenza A virus subtype H5N1 revised classification of Santalales. Taxon 9:538–558.
Renner SS. 2004. Plant dispersal across the tropical Atlantic past times current of air in addition to sea currents. International Journal of Plant Sciences 165:S23–S33.
Su H-J, Hu J-M, Anderson FE, Der JP, Nickrent DL. 2015. Phylogenetic relationships of Santalales alongside insights into the origins of holoparasitic Balanophoraceae. Taxon 64:491–506.
Vidal-Russell R, Nickrent DL. 2007. The biogeographic history of Loranthaceae. Darwiniana 45:52–54.
Vidal-Russell R, Nickrent DL. 2008a. Evolutionary relationships inwards the showy mistletoe menage unit of measurement (Loranthaceae). American Journal of Botany 95:1015–1029.
Vidal-Russell R, Nickrent DL. 2008b. The get-go mistletoes: Origins of aerial parasitism inwards Santalales. Molecular Phylogenetics in addition to Evolution 47:523–537.
Wilson CA, Calvin CL. 2006. An source of aerial branch parasitism inwards the mistletoe family, Loranthaceae. American Journal of Botany 93:787–796.