[jQuery] [validate] required that select input's option is anything other than default

[noon]

I'm trying to throw the field is required option on a select when its
selected option is my default option of dashes/0.  I might be going
about this the complete wrong way with the required (dependency-
callback). Help is appreciated.  My HTML/JS may make more sense than
this quesiton

HTML:
<select name="threshold" id="threshold" class="required">
        <option value="0"
selected="selected">&mdash;&mdash;&mdash;&mdash;&mdash;</option>
        <option value="65">65&#37;</option>
        <option value="70">70&#37;</option>
        <option value="75">75&#37;</option>
        <option value="80">80&#37;</option>
        <option value="85">85&#37;</option>
        <option value="90">90&#37;</option>
        <option value="95">95&#37;</option>
        <option value="100">100&#37;</option>
</select>

JS:
$('#mount-form').validate({
        rules: {
                threshold {
                        // I don't want to allow the selected option be 0
                        required: function(element) {
                                return $('#threshold option:selected').val() == 
'0';
                        }
                }
        }
});