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    The Walking Whales

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      “Yeah! But where is the rest of it?”

      We both frantically search for more in the bag of pieces.

      Geological age-wise, our new whale falls between  Ambulocetus and

      the basilosaurids. The sacrum of those two is very different: four firmly

      fused vertebrae in the former, no fused sacral vertebrae at all in the lat-

      ter.  That  makes  the  difference  between  being  able  to  support  one’s

      weight on land and not, so this is very important in understanding our

      new whale. Ellen and I keep on going through our fossils, finding more

      pieces. I glue them onto the growing sacrum with white Elmer’s glue. It

      takes a while to dry, and I am impatient, looking and trying to fit more

      fragments  before  already-glued  joints  have  dried.  Some  come  apart

      from my handling the fossil. Ellen notices my impatience and takes the

      sacrum from me without saying anything, firmly but gently. I know bet-

      ter than to dissent. She is the fossil preparator. Things progress more

      slowly, but now we need to glue each joint only once. Eventually, she fits

      a nearly complete sacrum together: four fused vertebrae, with a large

      joint for the pelvis. This guy could certainly stand on land.

      Still high on the success of our reconstructive surgery on the sacrum,

      I keep sorting through our bags of fossil chips. My eye is drawn toward

      a bone the size of a toffee, and also that color. It is broken on three of

      its four sides, indicating that it was part of something bigger, and the

      breakage also explains why I ignored it before. However, the fourth side

      shows two holes; they’re for teeth! A shiver runs over my back. “Sunil,

      I’ve got a jaw.”

      He looks up. The cavities that hold the left and right teeth, the alve-

      oli, are very close together, indicating that the jaw is very narrow. We

      both know what this means: this is one of the narrow-snouted whales

      for which we have fragmentary skulls. It allows us to identify the speci-

      men as a remingtonocetid.

      Eventually, this new  whale  will  receive  the  name  Kutchicetus min-

      imus, the “smallest whale from Kutch” (figure 31).1

      Over time, too, it becomes clear what the big Y was: the impression

      of the underside of the lower jaw. The long stem is the part where the

      left and right jaw touch; the short arms are the left and right parts as

      they diverge. The flute look-alike from Babia Hill, mentioned in chapter

      6, would make just such an impression, and, indeed, they represent the

      same species.

      As  Kutchicetus becomes well known, a company that makes museum

      exhibits, Research Casting International, puts it all together and casts

      it  in  some  fancy  plastic,  for  use  in  museum  displays.  Peter  May,  its

      The Otter Whale | 107

      figure 31. Life reconstruction of the Eocene whale Kutchicetus minimus, which lived

      in India around forty-two million years ago. Kutchicetus and other remingtonocetids

      were probably fish eaters, and were able to walk around on land.

      director, and I get all the bones together, and his team makes mirror

      images of the bones for which we only have one side. For the feet, there

      is nothing to mirror image because we found no fossils of them. I do

      not want the feet reconstructed, because I do not know what they

      looked like. We decide that he will use wire to indicate where the toes

      were, thus leaving it very clear that we do not have those parts.

      108    |    Chapter 8

      Then I ask Carl Buell, a scientific illustrator, to make a drawing of the

      animal. I know Carl. He is picky and precise. He asks for details—this

      view, that bone, things that I have never thought about.

      “How are the lips, are they floppy like a dog, or tight like a whale?”

      Carl asks in his crackling voice that betrays that he is not a young man.

      Carl knows his stuff—anatomy, function—he is also passionate. I say

      that I do not know the answer to his question.

      “It has this long, narrow snout, that’s crazy, I’d love to wrap my pen-

      cils around that—a whale looking like a gharial.” He is right. This whale

      does look like the narrow-snouted crocodilians that inhabit India and

      Pakistan.

      “So what do its feet look like?”

      “We don’t have the feet. We didn’t find them.”

      It is quiet for a second. He’s clearly disappointed.

      “You don’t have any bones from the feet—nothing, no phalanges, no

      carpals, nothing?”

      “I have half a bone, probably a phalanx, it won’t help you.”

      Quiet again. I break the silence. “What are you going to do with it in

      the reconstruction?” I ask, somewhat worried that he may not think the

      project is feasible.

      “Oh, I’ll figure out something.” This does not sound good. I want to

      know what is he planning.

      “I don’t want you to make them up, OK?”

      “You’ll see, you’ll like it.”

      His voice changes to the tone of a doctor who comforts a worried

      patient,  but  does  not  want  to  explain.  I  trust  Carl,  so  I  don’t  push

      him. He  wants to  know  what  to  use  as a  scale, so  people  will  know

      how small it was. He proposes a shorebird. People have some sense of

      what  size  those  are,  and  Carl  knows  that  they  were  around  in  the

      Eocene.

      A few days later, Carl sends me some sketches, the head from dorsal

      and from the side—he is clearly struggling with it, it is so different from

      other mammals—but no reconstruction of the body. I still do not know

      how he is going to solve the hand-and-foot problem, and I am dying to

      know. Then, eventually, I get a sketch of the entire animal. I rush to open

      the file. There are three individuals, showing three different views of the

      head, and he’s put them at the shoreline, feet in the water, invisible, the

      rest of the animal above the water, visible. Brilliant, such a simple solu-


      tion, except that I would not have thought of it. The bird in the back-

      ground looks good, too.

      The Otter Whale | 109

      remingtonocetid whales

      Carl’s reconstruction put some flesh on the bones of the remingtonocetid

      whales, initially discovered by Ashok Sahni and his student V. P. Mishra.

      After that initial description,2 Sahni sent another student, Kishor Kumar,

      to Kutch to collect more whales. Bad weather made fieldwork impossi-

      ble for much of Kishor’s stay, but he did find the most complete skull of

      Remingtonocetus known at that time.3 He also collected new material

      for another whale that Mishra had discovered: Andrewsiphius, named

      after C. W. Andrews, a British paleontologist who worked in Egypt and

      described many basilosaurids. Realizing that Andrewsiphius and Rem-

      ingtonocetus were part of a unique Indo-Pakistani radiation of whales,

      Kumar and Sahni combined Remingtonocetus and Andrewsiphius into

      a new family: Remingtonocetidae. Since then, no remingtonocetid has

      ever been found outside of the Indian continent, but three additional

      genera have been described: Dalanistes, based on specimens from cen-

      tral Pakistan4 and Kutch,5 Kutchicetus from Kutch, and Attockicetus,

      which came from the same rocks as Ambulocetus: the Kuldana Forma-

      tion of Northern Pakistan.6

      Remingtonocetids differ from other Eocene cetaceans in having long

      snouts, tiny eyes, and big ears. Based on what is known for Kutchicetus,

      its body looked like that of an otter: short legs, and a long, powerful

      tail. In contrast, the long, narrow snout makes the head look more like

      a gharial (figure 33). Kutchicetus was the smallest remingtonocetid, the

      size of a sea otter; Dalanistes was the largest, weighing maybe as much

      as a male sea lion. Indian remingtonocetids are known from rocks forty-

      two million years old.7 Attockicetus is older, the same age as Ambuloce-

      tus, approximately forty-eight million years, and the remingtonocetids

      from central Pakistan are between thirty-eight and forty-eight million

      years old.8

      Feeding and Diet. It is easy to imagine that the long snout helped rem-

      ingtonocetids catch fish. If Ambulocetus lived like a crocodile, capturing

      large, struggling prey, remingtonocetids were more delicate, lashing out

      quickly with their sharp teeth when a fish came close.9 The front teeth of

      Kutchicetus are long and slender, good for piercing and checking slippery

      prey in a dash, but not for holding powerful struggling prey. The molars

      are small, but tooth wear shows that Remingtonocetus chewed its food,

      unlike modern whales; its teeth worked like those of basilosaurids and

      ambulocetids. These molars cut like scissors, with sharp shearing edges

      figure 32. Life reconstruction of the remingtonocetid whale Kutchicetus. Fossils of

      hands and feet were not discovered for this whale, which means that the artist

      reconstructing the animal needs to be creative.

      The Otter Whale | 111

      figure 33. The skeleton of the Eocene whale Kutchicetus minimus. Soccer ball is

      22 cm (8.5 inches) in diameter.

      (figure 34). No part of these teeth is involved in crushing food, unlike

      Ambulocetus. Analysis of the stable isotopes of the teeth is consistent

      with a fish diet, and further study may refine this.

      The flute look-alike mentioned in chapter 6 is a Kutchicetus jaw from

      Babia Hill. All its teeth fell out after death but before burial,10 but count-

      ing sockets for the teeth (the alveoli) reveals what the dental formula is.

      As in most early whales, there are three incisors, one canine, four premo-

      lars, and three molars in both upper and lower jaw: 3.1.4.3/3.1.4.3.

      Some jaws for Remingtonocetus and Dalanistes do still have teeth, and

      surprisingly, the lower molars look like those of basilosaurid whales

      (figure 34), with multiple cusps of decreasing size lined up from front to

      back.11 However, these teeth are unlike basilosaurids’ in that they are

      slender and delicate, not built to mince tough or hard food. In Andrews-

      iphius, there are three low and flat cusps on a lower molar, lined up in a

      row, with the middle cusp barely higher than the others. It is not clear

      whether this unusual shape somehow related to a specialized function.

      Remingtonocetid molars are specialized, unlike those of ambu-

      locetids, which retain the shape of archaic land mammals with a high

      front (the trigonid) and a low back (the talonid). The premolars in rem-

      ingtonocetids have simple, triangular cusps. In Andrewsiphius and

      Remingtonocetus, most premolars have two roots, but in Kutchicetus

      there is only one root per tooth. In modern whales, there is never more

      than a single root per tooth.

      The most unusual feature of the jaws of remingtonocetids is the long

      area of contact between left and right lower jaw. This area is called the

      mandibular symphysis (figure 25). In ambulocetids and basilosaurids, the

      left and right lower jaws are connected by ligaments; there is no bony

      fusion across the mandibular symphysis. This is also the case in most

      Remingtonocetus, although there is a bony connection in old individuals.

      In Andrewsipius and Kutchicetus, the left and right jaws are joined by

      Toward upper teeth

      Cheekside of jaw (labial)

      (occlusal)

      LEFT LOWER MOLAR AS To front of jaw

      To front of jaw

      SEEN FROM OUTSIDE

      (anterior)

      (anterior)

      (LABIAL VIEW)

      LEFT UPPER MOLAR IN OCCLUSAL VIEW

      Artiodactyla: Indohyus

      Four large cusps, Four large cusps,

      val eys between

      one small cusp,

      cusps.

      val ey between

      cusps.

      RR 102

      RR 209

      Pakicetid whale

      Only two large cusps One main cusp lost,

      Pakicetus

      and one small remain one small cusp lost,

      valleys gone.

      valley smaller.

      H-GSP

      Molar morphology

      H-GSP

      96334

      similar in ambulocetids

      18470

      Remingtonocetid whales

      Another main cusp lost, Remingtonocetus IITR-SB 2605

      valley gone,

      Two large cusps remain,

      new cusp added

      one new cusp formed

      anteriorly.

      in front of these.

      Andrewsiphius

      IITR-SB 2723

      Andrewsiphius IITR-SB 3153

      Protocetid

      Two large cusps remain.

      Similar to pakicetids

      whales

      and ambulocetids.

      IITR-SB

      3189

      IITR-SB

      4122

      Basilosaurid

      Three new cusps

      Similar to

      whales

      added posteriorly.

      remingtonocetids,

      but with two new cusps

      added posteriorly.

      MMNS 2339

      USNM 11962

      figure 34. Left lower (left column) and upper (right column) molars of Eocene whales

      and the artiodactyl Indohyus, showing the vast differences in the topography of teeth.

      O
    utline diagrams for upper molars show how the position of cusps changes in

      evolutionary time. Indohyus is discussed in chapter 14.

      The Otter Whale | 113

      bone: this is called a fused symphysis. An unfused symphysis allows for

      some independent movement of the jaws during chewing, and most small

      mammals have unfused jaws, for instance dogs, cats, rabbits, and rats.

      Larger animals that eat plants, such as horses, cows, elephants, rhinos,

      and hippos, tend to have fused symphyses. Large, long-snouted animals,

      such as crocodiles, also tend to have fused symphyses. The long symphy-

      sis, fused or unfused, gives the jaw strength when it is slapped shut, pos-

      sibly preventing teeth from interlocking incorrectly (misocclusion).

      Breathing and Swallowing. The nose opening of remingtonocetids is

      near the tip of the snout, which is where it is in land mammals. With the

      long snout, it may have allowed the whales to lie in wait in deeper water,

      with the tip of their nose above the water, and thus avoid the need to

      come to the surface to breathe while hunting. However, a nose opening

      that far forward might be helpful for other reasons. For remingtonocetids,

      freshwater conservation, in the face of the salty ocean they lived in, could

      be important. Modern seals use their nasal cavity to retrieve water from

      exhalation: water vapor coming from the lungs condenses in the nasal

      cavity and is taken up by the tissues inside the nose.12 It is possible that

      the long nasal cavity in remingtonocetids served this function.

      The remainder of the skull has its peculiarities too. The hard palate

      of Remingtonocetus extends nearly to the area of the ears, as in Ambu-

      locetus, although it does not reach as far down (ventral) as in Ambu-

      locetus. There is a prominent midline crest on the hard palate, probably

      for the attachment of the chewing muscles that attach to its lateral side:

      the left and right medial pterygoid muscles. The medial pterygoid is a

      powerful mouth-closing muscle, useful in a fish eater that clamps its

      teeth down fast on prey. In closing the mouth, the medial pterygoid

      works with two other muscles: masseter and temporalis. Temporalis

      attaches to the side of the skull, as well as to a crest on top of the skull

      (the sagittal crest, figure 29), and those bony attachments suggest that it

     


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