Find Job Calling Another Job
How can we find out if this is being called by another job?

Search all your job steps for the string with job name that ran by other job (at least that is what you suspect).
This query is from this website.

USE [msdb]
GO
SELECT  j.job_id,
    s.srvname,
    j.name,
    js.step_id,
    js.command,
    j.enabled 
FROM    dbo.sysjobs j
JOIN    dbo.sysjobsteps js
    ON  js.job_id = j.job_id 
JOIN    master.dbo.sysservers s
    ON  s.srvid = j.originating_server_id
WHERE   js.command LIKE N'%KEYWORD_SEARCH%'
GO


why would there not be any history for the job that ran?

Depending of how your job history is set up.  See my blog post.
Another good reference here.