New Sensory Organ in Rorqual Whales

This new organ may be responsible for the large size of Rorqual whales, such as this Fin whale

Another for the ‘no idea what he’s talking about’ pile, I’m afraid: Organ Discovery Shows Why Whales Didn’t Evolve, by Brian Thomas.

Rorqual whales are a subgroup of the Baleen whales – the filter feeders – and include the blue whale, along with many other large whales such as the fin whale above. Baleen whales (order Mysticeti, as they are called in the paper) have two separate (left and right) unfused halves to their lower jaw. In the Nature paper Thomas discusses, Discovery of a sensory organ that coordinates lunge feeding in rorqual whales, a sensory organ has been found to be located in the gap between the two jaw bones of rorquals, and is hypothesised to play an important role in these whales lunge-feeding behaviour:

Despite the antiquity of unfused jaws in baleen whales since the late Oligocene (~23–28 million years ago), this organ represents an evolutionary novelty for rorquals, based on its absence in all other lineages of extant baleen whales. This innovation has a fundamental role in one of the most extreme feeding methods in aquatic vertebrates, which facilitated the evolution of the largest vertebrates ever.

What is this organ exactly? It would appear that, in rorquals, the joint between the two halves has developed the ability to relay information about how it is being deformed by the independently moving jawbones. Again, from the paper:

Midline sagittal cuts along the mandibular symphysis showed that the sensory organ is mostly located on the dorsal half of the region between the symphyseal surfaces of the mandibles, and occupies a roughly spheroidal cavity. The organ is bound on all sides by dense connective tissue; the inner surface of the cavity is lined by a discontinuous squamous layer of cells and filled with a viscous gel-like matrix. The gel-like matrix supports numerous small connective tissue papillae that extend from the inner surface and sometimes cluster in irregular numbers within the cavity. Notably, the papillae contain nerves and encapsulated nerve termini (Fig. 2).

Following initial observations, it was suggested that the mandibular symphysis in fin whales contained a synovial cavity. Our results show that the symphysis is unlike a typical synovial joint with cartilage. Instead, it is bridged by very dense connective tissue, with cruciate fibres, but without true or patent ligaments that originate from the symphyseal groove. In addition, our anatomical and histological analyses indicate that its overall geometry and specialized tissues satisfy the criteria of a sensory organ. Specifically, we argue that the organ responds to localized changes in jaw configuration during lunge feeding, in which the rotation of the bowed jaws will cause deformation of the symphysis, similar to an intervertebral joint. This action provides the mechanical input to the sensory organ, which the brain receives through the mandibular branch of the trigeminal nerve (Fig. 3).

Now, what does Thomas do with this?

Rorqual whales, including blue whales and minke whales, don’t have teeth. Instead, they eat tiny sea animals by filtering water with comb-like bristles in their giant mouths called “baleen.” Working in symphony with an array of rorqual-specific traits, a newly discovered sensory organ builds an even stronger case for their special creation.

According to him the “complex” (and poorly understood) system used by rorqual whales to lunge-feed could not have evolved, because shut up:

A subset of baleen, rorqual whales eat through a process known as “lunge feeding” that requires a long list of fully formed features. One of those unique traits, essential for the whale’s feeding, involves the mouth and the jaw—the accordion-like skin folds on the throat greatly expand when they swallow huge mouthfuls of prey-laden water.

The problem with this line of argument is that just because the whales use, and need to use, all these features doesn’t mean that they all had to turn up at once. You could theoretically filter-feed with just baleen, for example, but once your competitors have further adaptations to increase their yield then you need it too. It’s analogous to an arms race: you may no be able to conceive an army now fighting with muskets but back in the way they were where it was at.

No combination of natural processes could have organized rorqual whale features, even considering toothed whales as possible evolutionary precursors. All the necessary traits were required for survival in the beginning, so they must all have popped into existence by a miraculous creation event.

This is just Thomas’ personal incredulity: just because he can’t imagine how it was done doesn’t mean it wasn’t. As a minor digression, have you ever heard of Aetiocetus, the toothed baleen whale? Whale evolution is actually fairly solid.

Thomas is also confusing the origins of baleen whales from toothed whales with the origins of rorqual whales from baleen whales. Other baleen whales did not and do not need the special rorqual whale features: his argument does not come close to holding water.

In the journal Nature, American and Canadian scientists described a previously unknown sensory organ situated in the front and center of the whale’s lower jawbone, where the bone is split into left and right halves. The organ measures and informs the brain about the resistance force upon the whale’s gaping mouth when lunge feeding. The unique organ also detects “dynamic rotation of the jaws during mouth opening and closure,” according to the report. In other words, without this sensory organ whales would not know how much force is too much when lunging through water—they could fatally damage themselves without this key sensory and data coordination device.

I don’t get that impression at all – that this organ prevents the whales killing themselves. It appears to be Thomas’ invention. Instead, it would seem that it helps them more efficiently lunge into more nutritious waters. But even assuming that B.T.’s claim is true, the organ is supposed to predate the increase in size of the whales. If they were small before they had this safety device it would not have mattered. But Thomas wants to spin it that a rorqual without the organ simply could not exist.

And according to the study authors, baleen whales need all of the following parts linked in precise proportions in order to eat: comb-like baleen to filter out food; expandable, accordion-like “ventral groove blubber” with cartilaginous support bars; the newly discovered sensory organ; a split jaw that is loosely connected to the skull; and tactile organs, “vibrissae,” along the chin that sense prey.

Again, you only really need these things once the neighbours have got them too. And they can be acquired one at a time, or they can evolve in parallel (with, say, the blubber growing and developing as the supports appear).

The researchers had difficulty describing when the newly discovered sensory organ might have evolved, and they did not even attempt to describe how it might have evolved. They suggested that if it evolved in pre-rorqual whales, then it was a “pre-adaptation for lunge feeding.”

Here’s a much longer quote:A Grey whale

The discovery of this organ raises questions about its role in the evolution of lunge feeding in whales. The ancestral mandibular condition of modern cetaceans was probably a fused (or strong sutural) symphysis with an elongate surface, as seen in nearly all basilosaurids, and a fused symphysis persists in modern toothed whales. By contrast, all living mysticetes possess unfused symphyses. Recently described fossil evidence from Janjucetus hunderi, a stem ‘toothed’ mysticete, demonstrates that the transition from fused to unfused mandibles occurred early in baleen whale evolution, with unfused symphyses in mysticetes having a late Oligocene antiquity (~23–28 Myr ago). Our investigations of the mandibular symphyses in living mysticetes show that bowhead, right and pygmy right whales (Balaena mysticetusEubalaena spp. and Caperea marginata, respectively) do not possess a gel-like cavity in their mandibular symphysis, although small papillae intruding into the connective-tissue matrix in this area are patent among adult and immature specimens (see Supplementary Information). The condition of the mandibular symphysis in grey whales (Eschrichtius robustus) has only been reported for a decayed neonatal specimen, although the suggestion of a mucoid centre is broadly similar with the morphology of the organ described here. On the basis of this equivocal evidence, we propose that the organ evolved either at the node of Balaenopteroidea (grey whales and rorquals), or along the stem to crown Balaenopteridae (rorquals). If the former, the organ is a pre-adaptation for lunge feeding; if the latter, the organ evolved in tandem with VGB and specializations of the mandible morphology, such as a laterally deflected coronoid process and flexible temporomandibular joints, which exhibit a degree of mandible rotation and oropharyngeal cavity expansion far greater than that of grey whales. Regardless of evolutionary sequence, we argue that multiple lines of evidence indicate that the sensory organ has a key role in lunge feeding by registering the rotation of the mandibles during a lunge and the expansion of the throat pouch through the YSF, all of which evolved before the extremely large body sizes observed in today’s rorquals.

Bolded is Thomas’ quote, along with some context above and below it. Basically, they’re not quite sure if the related grey whales also have this organ or not. Resting on that unknown is whether or not the organ evolved before or with the other features needed for lunge feeding. But according to Thomas:

But this contradicts a fundamental evolutionary tenet—natural forces are supposed to have no foresight. How could nature prefabricate precisely-fitted machine parts that would only function after generations of future whales had finally evolved all the other machine parts?

You see what I mean by him not knowing what he’s talking about? It’s like saying that having five fingers is utterly useless until tool use is invented.

Consider it this way: for the organ to be a ‘pre-adaption’  it must exist in grey whales, which don’t lunge. If it only has a function as part of the lunging machinery it would then be utterly useless in the grey whales. But as, at least according to creationists, there is no such thing as a truly useless organ that cannot possibly be the case. Thomas isn’t even being internally consistent.

The study authors also suggested that if the organ evolved at the same time that rorqual whales supposedly branched off of the baleen whale lineage, then “the organ evolved in tandem with the ventral groove blubber and specializations in mandible morphology.”

The only difference between “evolving in tandem with [the necessary rorqual feeding] specializations” and God creating all those specializations at the same time is that the former calls upon deaf, dumb, and blind nature to perform what only an all-knowing, all-seeing God of Creation could have wrought. The credit for rorqual whale design and construction is rightfully His.

“The only difference”!? Thomas doesn’t appear to even understand what the ‘tandem’ phrase means! It’s a good thing he ended here, before he made a fool of himself further.

2 thoughts on “New Sensory Organ in Rorqual Whales

  1. Scientists find something new, that we didn’t know about previously (and certainly, Darwin didn’t know about it). Thus evolution is proven false.

    Why is every creationist argument some variation on this?

  2. Nicely done.

    Perhaps Mr. Thomas can explain why this “all-seeing God of Creation” chose to create (in addition to intermediate forms like Aetiocetus) tooth buds in the embryos of baleen whales? Just trying to throw us off his scent I guess.

    Jerry Coyne did a related blog post on this a while back that included an excellent photograph of a mysticete embryo (a fin whale in this case) dissected to show the tooth buds. See:

    http://whyevolutionistrue.wordpress.com/2010/07/22/baleen-whales-a-lovely-transitional-form/

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