Crocodylus halliı, Murray & Russo & Zorrilla & McMahan, 2019

Murray, Christopher M., Russo, Peter, Zorrilla, Alexander & McMahan, Caleb D., 2019, Divergent Morphology among Populations of the New Guinea Crocodile, Crocodylus novaeguineae (Schmidt, 1928): Diagnosis of an Independent Lineage and Description of a New Species, Copeia 107 (3), pp. 517-523 : 521-522

Crocodylus halliı new species

urn:lsid:zoobank.org:act:2B819FD7-B74C-42B4-A85B-7D4B93D96105

Hall’s New Guinea Crocodile

Figure 7

Holotype.— USNM 211290, Papua New Guinea, Western Province, Balimo, Aramia River Lagoon, – 8.00589 S, 142.938 E, Charles A. Ross, 27 November 1977 [skull with mandibles; sex unknown] ( Fig. 7 ).

Paratypes.— LSUMZ 44734 , Papua New Guinea, Western Province, Lake Murray District, Agu River, Philip Hall , 14 January 1981 [skull; female] ; LSUMZ 44735 , Papua New Guinea, Western Province, Lake Murray District, Lake Murray, Philip Hall , 14 January 1980 [skull; sex unknown] ; USNM 211298, Papua New Guinea, Western Province, Balimo, Aramia River Lagoon, – 8.00589 S, 142.938 E, Charles A. Ross, 27 November 1977 [skull with mandibles; sex unknown] .

Non-type material.— LSUMZ 44722–44732 , 44734–44738 , 44740–44746 , UF 145927 , 24 , Lake Murray District ; MCZ 153039–153040, 2 , Binaturi River ; USNM 211290, 211293, 211294, 211296, 211298, 211300–211301, 7, Aramia .

Diagnosis.— Crocodylus halli is readily separated from C. novaeguineae based on a longer frontal bone (versus shorter in C. novaeguineae ); a shorter maxilla and nasal (versus longer in C. novaeguineae ); long and wide postorbital and squamosal (versus short and narrow in C. novaeguineae ); and a wider palatine of pterygoid that extends posteriorly (versus narrow and medially oriented in C. novaeguineae ). Additionally, C. halli possesses no more than four non-contiguous postoccipital scutes, versus four to six contiguous post-occipital scutes in C. novaeguineae .

Species description and variation.— Variation in morphology of adult Crocodylus halli exists among drainages, with specimens from Lake Murray exhibiting a skull width that is more than half of the skull length (posteromedial squamosal to anteromedial premaxilla), resulting in the

appearance of a stocky and wide head in adults. Specimens from Aramia River have generally longer maxilla and shorter postcranial elements than Lake Murray individuals, while maintaining shorter maxilla and longer postcranial elements than C. novaeguineae . Juveniles retain morphology consistent with ontogenetic constraints, exhibiting a relatively enlarged orbit and compressed postcranial elements.

Distribution.— Crocodylus halli occurs within drainages south of the Central Highlands of Papua New Guinea in swamps, rivers, lakes, and occasionally estuaries.

Natural history.— Females of C. halli nest in the rainy season (November–April) and lay larger eggs in smaller clutches than C. novaeguineae , which nests near end of the dry season (July– November; Cox, 1985; Hall, 1985; Hall and Johnson, 1987).

Etymology.— The specific epithet recognizes the fieldwork and research of Philip Hall whose contributions provided the

initial framework for supporting distinctiveness of this species.

Figures

Fig. 7. Holotype of Crocodylus halli, USNM 211290.