Microgobius ecuadorensis, Schwarzhans & Aguilera, 2024

Schwarzhans, Werner W. & Aguilera, Orangel A., 2024, Otoliths of the Gobiidae from the Neogene of tropical America, Swiss Journal of Palaeontology (13) 143 (1), pp. 1-129 : 62-64

publication ID	https://doi.org/10.1186/s13358-023-00302-5
persistent identifier	https://treatment.plazi.org/id/492D87AA-FF96-FFDB-0236-FA7060F9F8B8
treatment provided by	Felipe
scientific name	Microgobius ecuadorensis
status	sp. nov.

Treatment

Microgobius ecuadorensis n. sp.

Figure 29j–q View Fig

Holotype NMB P15679 View Materials ( Fig. 29l View Fig ), Tortonian , Angostura FM, Ecuador, NMB 19301 View Materials .

Paratypes 7 specimens Tortonian, Angostura FM , Ecuador: 1 specimen PPP 3369 ( NMB P15680 View Materials ) , 2 specimens PPP 3444 ( NMB P15681-82 View Materials ) , 4 specimens PPP 3301 ( NMB P15683-86 View Materials ) .

Referred specimen 95 specimens Tortonian: 94 specimens Angostura FM , Ecuador: 3 specimens NMB 19301 View Materials , 28 specimens PPP 3297 , 51 specimens PPP 3301 , 10 specimens PPP 3369 , 3 specimens PPP 3372 , 1 specimen PPP 3444 ; 1 specimen Tuira FM , Pacific Panama, Darien, PPP 1132 .

Etymology Named after Ecuador, the country from which the type specimens originate.

Diagnosis Otolith size up to 2.0 mm in length. OL:OH=0.78–0.9. Otolith shape high-bodied; dorsal rim high, regularly crenulated, with rounded, obtuse middorsal angle and short rounded postdorsal projection. Sulcus moderately large and wide, with broad ostial lobe and rounded caudal tip; OL:SuL=1.5–1.7; sulcus inclination angle 15–20°. Subcaudal iugum long, moderately wide. Ventral furrow distant from ventral rim of otolith, regularly curved.

Description Otolith size up to 2.0 mm in length (holotype 1.75 mm). OH:OT = 3.9–4.2. Otolith shape high-bodied. Dorsal rim high, regularly crenulated, with broadly rounded predorsal angle, obtuse to rounded middorsal angle and short broadly rounded postdorsal projection. Anterior rim near vertical or slightly inclined towards dorsal; posterior rim vertical to slightly inclined and with indistinct central concavity. Ventral rim flat to slightly curved, horizontal. Preventral angle orthogonal, postventral angle rounded. All rims slightly undulating and dorsal rim regularly crenulated.

Inner face flat in vertical direction and slightly bent in horizontal direction. Sulcus moderately long and wide, with broad ostial lobe; cauda straight, with rounded tip, slightly deepened; sulcus inclination angle 15–20°; OL:SuL = 1.5–1.7. Subcaudal iugum long, moderately wide, may expand over posterior tip of cauda in juvenile specimens ( Fig. 29q View Fig ). Dorsal depression moderate in size, with indistinct margins. Ventral furrow distinct, distant ventral rim of otolith and regularly curved. Outer face with slight ventral umbo, slightly ornamented.

Discussion Microgobius ecuadorensis is characterized by its broadly crenulated dorsal rim, which distinguishes it from most of its congeners except for M. crocatus and M. verecundus . It differs from M. crocatus in the higher and less regularly curved dorsal rim and the shorter sulcus (OL:SuL = 1.5–1.7 vs 1.4–1.55). Microgobius ecuadorensis differs from the parallel occurring M. verecundus in being mostly more compressed (OL:OH = 0.78–0.9 vs 0.86–0.9) and thinner (OH:OT = 3.9–4.2 vs 3.5–3.8) and the usually more regularly developed crenulation of the dorsal rim.