În sistemul american, echivalentul pontatorului este "timekeeper".

There are many different ways to record employees' work times. One is by designating a person to serve as timekeeper and manually enter starting and stopping times on a piece of paper. Another is to have employees fill in their own work times. Employers can have employees punch a time clock. Some companies with advanced systems have employees "swipe" their company ID cards or badges through a device that electronically records the time and enters it into a timekeeping database. Finally, some companies ask employees to enter their own times on their computers, or else use an automated voice-response system in conjunction with a touch-tone telephone to record their times. Regardless of the method used, it is subject to the requirements of part 516 and the "best evidence" rule in the event of a dispute.

http://www.twc.state.tx.us/news/efte/b_recording_working_tim...

Tot aici vei găsi şi un glosar care ţi-ar putea fi de ajutor.
E cam greu să faci o paralelă ţinând cont de faptul că sistemele sunt atât de diferite :) Bănuiesc că şi în UK se foloseşte acelaşi termen.

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Note added at 13 ore (2009-06-17 07:58:13 GMT)
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Eventual, persoana care se ocupă cu evidenţa orelor lucrate şi a prezenţei angajaţilor, poate fi numită şi time clerk. Caut niste referinte...

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Note added at 13 ore (2009-06-17 08:21:48 GMT)
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Am gasit urmatoarea fisa de post: payroll clerk
Payroll clerks compute and record the earnings owed to each company employee on a computer and ensure employees are paid on time. This recording is known as posting. The information for the calculations is often taken from paper worksheets and work tickets. In offices where automated timekeeping systems are in place, the payroll numbers are already in the computer system, and the payroll clerks are required to check the electronic data for errors....
http://careers.stateuniversity.com/pages/169/Payroll-Clerk.h...

Cred ca din cele trei variante propuse, una poate fi satisfacatoare (avand in vedere contextul pe care-l ai). Succes!