On October 15, 1936, model IBIS was introduced as the second economy model (the first was Rappen) (Pelikan Schreibgeräte)⁽⁴⁾. Like "Pelikan", the model was named after the name of  a bird⁽⁵⁾⁽⁶⁾. Its slogan was "Ein Füllhalter niederer Preislage, aber gut, zuverlässig und betriebssicher; Pelikan catalog No.70 (1938)"⁽⁷⁾.

IBIS has similar shape to its predecessor Rappen. It comes between Rappen and Pelikan in length (IBIS is 2mm longer than Rappen and 2mm shorter than 100). The outer and inner diameter of the barrel is same as Rappen and 100, and fits the filling mechanism of 100 (DO NOT try!!!). The section also takes the socket of 100. As the pen doesn't have a sleeve or "binde", the body is slimmer than 100 by the sleeve width of 100. The barrel has a small step near the section (Fig.9 arrow). When cap closed, its rim comes just to this step. Having the same size and shape as IBIS, piston filler Rappen (1937) is sort of its variant.

What should be noted is the color of the barrel. According to Christof Zollinger (Fountain Pen Board), original IBIS was blackened inside of the barrel with sort of a paint. Most of them have decolored over time and look like a demonstrator (Fig.7). The ink window has been stained with ink and/or discolored by sun light. Please see Fig.11 for the images closer to the original barrel.

The filling mechanism itself is same as that of 100. The notch in the piston guide suggests that it was produced around 1937 (here) (Fig.9 arrow head).

The nib imprint has millesimal fineness, which conforms to the nibs of other models made in 1937 and after. There is no nib specification on nib or anywhere else⁽⁸⁾.

My pen has an unusual cap clip ending in a diamond shaped point. The clip of this style is attributed to Günther Wagner’s Gdańsk-Wrzeszcz (German: Danzig-Langfuhr) plant production, and it is often referred to as "Danzig clip" (Pelikan’s Perch). What model(s) had been produced in the plant is still controversial (Pelikan’s Perch). Comparing the lengths of clips (Fig.11), the clip seems to be original for this model. The cap tube is adorned with a single cap ring like Rappen. My pen has no vent holes nor "IBIS" imprint on it (Fig.9). In summary, IBIS was the "hybrid" of "Rappen" and "Pelikan". While assuming the appearance of "Rappen", the model carried the "Pelikan" filling mechanism. Although it was the economy model, IBIS had no less quality than the flagship Pelikan.

Note;⁽¹⁾As seen in catalogs (Pelikan catalog No.70 (1938), Pelikan catalog No.75 (1939)), IBIS was advertised as "IBIS fountain pen", independently of "Pelikan fountain pen". IBIS had model No.130. When IBIS was introduced, Pelikan model No.100, 101, 110, 111, and 112 were already on the market. Why IBIS was No.130, not No.120? I don't have any source, but my guess is that Rappen should have been model No.120, so model No.120 was not used.
⁽²⁾We can see that "IBIS" was patented as a brand name like "Pelikan" and "Rappen". Why the name is all in CAPITAL LETTERS is not clear.
⁽³⁾Ebonite was also possible for material (Pelikan Schreibgeräte).
⁽⁴⁾The price was around 7.50 RM (Reichsmark), not too dissimilar from that of Rappen (Pelikan’s Perch).
⁽⁵⁾Ibis are a group of long-legged wading birds belonging to the family Threskiornithidae, that inhabit wetlands, forests and plains. The family Threskiornithidae belongs to the order Pelecaniformes. The order also includes the family Pelecanidae. So, ibis are biologically related to pelicans.
⁽⁶⁾According to Wikipedia, Rappen also has something to do with the name of birds. The origin of the term can be traced back to the Rappenpfennig, a form of the penny minted in Freiburg im Breisgau in the 13th century featuring an eagle, which later on was interpreted to depict a raven (German Rabe; the word is thus a cognate of its German homophone Rappen referring to a "raven"-black horse).⁽⁷⁾"A fountain pen of good quality, moderate in price and reliable in use; Pelikan catalog No.75 (1939)."
⁽⁸⁾Some time in the following years, it became imprinted on the piston guide (Fig.12).