My One day old baby has no fontanelle?

Molding initially. As babies make their way through the birth canal, their skull plates overlap to a degree to pass through. It is not unusual for this to result in a small fontanelle at birth. Your hospital physician will verify that the plates are " mobile" by exam. The overlap resolves within the first week or two of life.
No biggie. Over several decades I have cared for normal newborns with a fontanelle size ranging from undetectable to 6 inches across.They all grew up and did fine. Your doc can monitor the kids usual parameters of head growth to verify things are okay.