reworked your sample creature a little better... does this add up properly?
SAMPLE GHUUNA
Here is an example of a ghuuna using a gnoll as the base creature and a hyaenodon as the base animal.
Ghuuna, Gnoll Form
Medium Humanoid (Gnoll, Shapeshifter)
HD: 2d8+2 plus 5d8+20 (58 hp)
Initiative: +0
Speed: 30 ft (6 squares)
AC: 17 (+3 natural, +2 leather armor, +2 heavy steel shield), touch 10, flat-footed 17
Base Attack/Grapple: +4/+6
Attack: Battleaxe +3 melee (1d8+2/X3) or shortbow +1 ranged (1d6/X3)
Full Attack: Battleaxe +3 melee (1d8+2/X3) or shortbow +1 ranged (1d6/X3)
Space/Reach: 5 ft/5 ft
Special Attacks: ---
Special Qualities: Alternate form, damage reduction 5/cold iron or magic, darkvision 90 ft, hyena empathy, immune to silver, low-light vision, scent
Saves: Fort +8 Ref +4 Will +1
Abilities: Str 15 Dex 10 Con 13 Int 8 Wis 13 Chr 8
Skills: Hide +3, Listen +5, Spot +6
Feats: Alertness, Iron Will (B), Power Attack, Run, Track (B)
Environment: Warm plains
Organization: Solitary, pack (2-5 plus 1-2 hyenas or 1 hyaenodon per ghuuna), or band (1-10 ghuuna plus 10-100 gnolls)
Challenge Rating: 4
Treasure: Standard
Alignment: Usually chaotic evil
Advancement: By character class
Level Adjustment: +4
Ghuuna, Hyaenodon Form
Large Humanoid (Gnoll, Shapeshifter)
HD: 2d8+2 plus 5d8+25 (58 hp)
Initiative: +3
Speed: 50 ft (10 squares)
AC: 20 (-1 size, +3 Dex, +8 natural), touch 12, flat-footed 17
Base Attack/Grapple: +4/+16
Attack: Bite +11 melee (1d8+8)
Full Attack: Bite +11 melee (1d8+8)
Space/Reach: 10 ft/5 ft
Special Attacks: Disease, ghuunism, trip
Special Qualities: Alternate form, damage reduction 5/cold iron or magic, darkvision 90 ft, hyena empathy, immune to silver, low-light vision, scent
Saves: Fort +12 Ref +7 Will +3
Abilities: Str 27 Dex 16 Con 21 Int 8 Wis 13 Chr 8
Skills: Hide +6*, Listen +5, Spot +6
Feats: Alertness, Iron Will (B), Power Attack, Run, Track (B)
Environment: Warm plains
Organization: Solitary, pack (2-5 plus 1-2 hyenas or 1 hyaenodon per ghuuna), or band (1-10 ghuuna plus 10-100 gnolls)
Challenge Rating: 4
Treasure: Standard
Alignment: Usually chaotic evil
Advancement: By character class
Level Adjustment: +4
Ghuunas in gnoll form are larger than average gnolls, and tend to intimidate their lesser cousins.
COMBAT
In animal form, ghuuna attack foes with their savage bite, trying to infect them with disease. In either form, ghuuna fight like a pack, using numbers to their advantage.
Alternate Form (Su): A ghuuna can assume the form of a hyaenodon.
Disease (Ex): Red ache; bite, Fortitude DC 15, incubation period 1d3 days, damage 1d6 Strength. The save DC is Constitution-based. Humanoids with the gnoll subtype are unaffected by this disease; instead, they are subject to ghuunism (see below).
Ghuunism (Su): Any humanoid with the gnoll subtype hit by a ghuuna's bite attack in animal form must succeed on a DC 15 Fortitude save or contract ghuunism. If the victim’s size is not within one size category of the ghuuna the victim cannot contract ghuunism from that ghuuna. Unlike lycanthropes and the curse of lycanthropy, afflicted ghuuna can pass on ghuunism.
Hyena Empathy (Ex): Communicate with hyenas, dire hyenas, and hyaenodons, and a +4 racial bonus on Charisma based checks against hyenas, dire hyenas, and hyaenodons.
Trip (Ex): A ghuuna that hits with its bite attack can attempt to trip the opponent (+11 check modifier) as a free action without making a touch attack or provoking an attack of opportunity. If the attempt fails, the opponent cannot react to trip the hyaenodon
Skills: *In hyaenodon form, a ghuuna has a +4 racial bonus on Hide checks in areas of tall grass or heavy undergrowth.